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S0021967320306440
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This paper analyzes the use of animal component free chromatographic materials for the efficient purification of the human fibroblast growth factor 2 . hFGF 2 is produced in
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Avoiding animal based materials in protein purification. Replacement of animal based ligand heparin in affinity chromatography. Alternative ligands can be mixed mode and pseudo biospecific ligands. Mixed mode chromatography as an alternative to heparin affinity chromatography.
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S0021967320306452
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Recycling counter current chromatography has been developed and widely used in preparative separation . Due to increasingly broader peaks with longer elution times recycling elution must be stopped before a peak overlap occurs resulting in the insufficient separation of target compounds . In this study the concept of
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The. concentration technique compressed effluent with separation effect. Unlimited recycling CCC was achieved by. concentration and recycling elution. URCCC strategy could increase recycling times until satisfied separation achieved. Naphthaquinones were isolated by URCCC with excellent resolution and yield 89.6 . The new strategy greatly expanded the application of CCC in preparative separation.
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S0021967320306488
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Effect of mobile phase composition on the enantioseparation of dipeptides on the chiral stationary phase Chirobiotic R was investigated using Ala Ala Leu Leu Gly Leu and Leu Gly as case studies . The lipophilicity of dipeptides was found to be an essential factor in the dependence of their retention on the methanol percentage the retention factor of lipophobic dipeptides increasing monotonously and that of lipophilic dipeptides changing according to an asymmetric U shaped trajectory as methanol concentration increases . The behavior of enantioselectivity as a function of the methanol content also depends on the lipophilicity of dipeptide . For lipophilic Leu Leu the dependence has a dome like shape and for more lipophobic dipeptides Ala Ala and Gly Leu it is an increasing function of the methanol concentration . The importance of solvation equilibria in the bulk liquid and on the surface of the stationary phase for the total retention is discussed from the thermodynamic point of view . Special consideration is given to the adsorption of the water methanol mixture on the surface of the Chirobiotic R stationary phase .
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Retention of dipeptides on Chirobiotic R was studied with methanol water eluents. Lipophilicity of dipeptide determines how retention depends on eluent composition. Solvation in the bulk liquid and on the surface is important for retention. Solvation on the surface and solvent displacement influence enantioselectivity. Adsorption of methanol water mixtures on Chirobiotic R was studied.
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S0021967320306506
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Simulation software for liquid chromatography can accelerate method development capabilities . In two dimensional chromatography this is particularly attractive because there are more method variables to consider provided simulations can account for the effects of injecting effluent from the first dimension separation into the second dimension column . In this paper we describe the adaptation of a previously described model to enable prediction of the profile of an injection pulse as it exits an Active Solvent Modulation valve and enters the second dimension column under a variety of flow rate and sample loop size conditions . Experimentally measured injection profiles were used to train empirical models capable of generating injection profiles as a function of sample loop volume and flow rate . The resulting parameters were then used to generate an injection profile for a loop volume not used in the training set . The resulting profile agreed well with the experimentally obtained profile for this sample loop . Finally chromatograms were simulated using previously developed simulation software incorporating the injection profile models developed in this work . Chromatographic peaks were simulated for valerophenone on an Agilent Zorbax Stablebond C18 stationary phase with an acetonitrile water mobile phase gradient . Results of simulations based on experimental injection profiles profiles predicted using the Forssn or global models and rectangular injection profiles were compared . Comparison of the resulting chromatographic peaks revealed good agreement between those produced using experimental profiles or the Forssn or global models with less than 0.3 deviations for retention times and less than 10 deviations for the peak widths .
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Injection profiles for second dimension of 2D liquid chromatography are measured. These injection profiles are successfully modeled. Modeled profiles agree well with experimentally obtained profiles. Modeled injected profiles are used with liquid chromatographic simulator.
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S0021967320306518
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This work demonstrates the development of a compact modular cost effective separation system configured to address a specific separation problem . The principles of the separation are based on gradient capillary liquid chromatography where the system consists of precision stepper motor driven portable syringe pumps with interchangeable glass syringes . Excellent flow rate precision of
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Portable and fully modular compact capillary liquid chromatography system has been developed. Custom built syringe pumps with a wide range of capillary flow rates. High sensitivity Z type UV absorbance detector with custom built passively cooled housing was evaluated. High repeatability of 1.5 RSD for peak area and 0.4 RSD for retention time was achieved.
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S002196732030652X
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Since decades cyclodextrins are one of the most powerful selectors in chiral capillary electrophoresis for the enantioseparation of diverse organic compounds . This review concerns papers published over the last decade dealing with the capillary electrophoretic application of single isomer cyclodextrin derivatives in chiral separations . Following a brief overview of their synthetic approaches the inventory of the neutral negatively and positively charged and zwitterionic CD derivatives is presented with insights to underlying structural aspects by NMR spectroscopy and molecular modeling . CE represents an ideal tool to study the weak non covalent supramolecular interactions . The published methods are reviewed in the light of enantioselectivity enantiomer migration order and the fine tuning of enantiodiscrimination by the substitution pattern of the single entity selector molecules which is hardly possible for their randomly substituted counterparts . All the reviewed publications herein support that cyclodextrin based chiral capillary electrophoresis seems to remain a popular choice in pharmaceutical and biomedical analysis .
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Chiral capillary electrophoresis methods using single isomer cyclodextrins reviewed. Brief summary of the synthetic challenges of single isomer selectors provided. Neutral anionic and cationic selectors applied over the last decade collected. Structure enantioselectivity relations of selector selectand interactions discussed. Structural insights provided for the enantioseparation mechanisms by NMR.
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S0021967320306531
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The potential of continuous bioprocessing is hindered by the bottlenecks of chromatography processing which continues to be executed in batch mode . Highlighting the critical drawbacks of batch chromatography this review underscores the transition that the industry has made by implementing continuous upstream process without devising a working model for downstream chromatography operations . Even though multitude of process development initiatives have commenced the review emphasizes the first principle models of chromatography on which these initiatives are built . Various models of continuous chromatography which are essential but not limited to multi column systems employed to congeal a unified process are reviewed . Advancements made by several mechanistic models and simulations to maximize productivity and performance are described in an attempt to provide the integral tools . The modeling tools can be used for development of a strong model based control strategy and can be embedded into the continuous chromatography framework . The review addresses the limitations and challenges of the current modeling methods for development of robust mechanistic modeling and efficient unit operation platform in continuous chromatography .
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The challenges and bottlenecks arising due to batch chromatography are identified. Merits of continuous multi column chromatography are provided. The modelings and technologies currently available for the continuous chromatography are summarized. The control strategy and gaps for implementation of continuous chromatography are described.
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S0021967320306543
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This study reports the use ofa natural deep eutectic solvent with hollow fiber microporous membrane liquid liquid microextraction for the multiclass determination of 11 compounds classified as emerging contaminantsin water . Different deep eutectic solvents were synthetized and Thymol Camphor wasused as extraction solvent . The Thymol Camphor was impregnated into the polypropylene membrane porous for 10min replacing commonly used solvents . The optimized parameters were obtained by multi and univariate models . Extractions were carried out for 50min using 1.5mL of water sample at pH 6 and without addition of salt while desorption was made in a mixture of acetone methanol for 15min . Separation quantification was conducted by HPLC with a diode array detection and calibration curves were obtained for each analyte . Determination coefficients higher than 0.9906 and limits of detection ranged from 0.3 to 6.1g L
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A simple easy and fast multiclass method for emerging contaminants determination is proposed. A natural deep eutectic solvent was successfully applied as extraction phase. Less than 1mL of organic solvent was used in the entire sample preparation process. Possibility of automation of the technique with 96 simultaneous extractions.
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S0021967320306555
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Downstream processing of large bionanoparticles is still a challenge . The present study aims to systematically compare some of the most commonly used DSP strategies for capture and purification of enveloped viruses and virus like particles by using the same staring material and analytical tools . As a model Human Immunodeficiency Virus 1 gag VLPs produced in CHO cells were used . Four different DSP strategies were tested . An anion exchange monolith and a membrane adsorber for direct capture and purification of eVLPs and a polymer grafted anion exchange resin and a heparin affinity resin for eVLP purification after a first flow through step to remove small impurities . All tested strategies were suitable for capture and purification of eVLPs . The performance of the different strategies was evaluated regarding its binding capacity ability to separate different particle populations and product purity . The highest binding capacity regarding total particles was obtained using the anion exchange membrane adsorber 5.310
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Systematic comparison of performance of common purification methods for eVLPs. Chromatin and eVLPs have similar size distribution in NTA measurements. Heparin affinity chromatography can separate eVLPs host vesicles and chromatin.
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S0021967320306567
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Ordered porous materials are attracting enormous attention due to their uniform pore structures particularly the magnetic photonic crystal microspheres which not only possess unique photonic crystal structure but also can achieve separation easily based on magnet . Here a two phase microfluidic self assembly synthetic system was established simply and employed for the preparation of three dimensional PCMs by using the emulsion droplet approach . One phase was an aqueous emulsion containing Fe
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Ordered macroporous magnetic silica photonic crystal microspheres were prepared. Droplet based flow microfluidic self assembly method was employed to prepare the microspheres. Particle size and content of the nanoparticles for self assemble affect the microspheres quality. The structural properties of the microspheres were characterized and studied. The method overcomes the nanoparticles disordered self assemble and the microspheres collapse.
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S0021967320306579
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Microwave ultrasonic assisted aqueous enzymatic extraction was applied to extract tiger nut oil . The conditions of MUAAEE were optimized by Plackett Burman design followed Box Behnken design . An oil recovery of 85.23 was achieved under optimum conditions of a 2 concentration of mixed enzyme including cellulase pectinase and hemicellulase particle size 600m microwave power 300W ultrasonic power 460W radiation temperature 40C time 30 min enzymolysis temperature 45C pH 4.9 liquid to solid ratio 10mL g and time 180min . Oil by MUAAEE revealed the similar fatty acid compositions triglyceride compositions thermal behaviour and flavour compared with oil by Soxhlet extraction while the oil quality of MUAAEE is superior to that of SE . Scanning electron microscopy revealed that structural disruption of tiger nut caused by MUAAEE facilitated the oil extraction . Results suggest that MUAAEE could be an efficient and environment friendly method for extraction of TNO .
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Microwave ultrasonic assisted aqueous enzymatic extraction MUAAEE is developed to extract tiger nut oil. MUAAEE is optimized by a Plackett Burman design followed a Box Behnken design. Physicochemical properties of Oil by MUAAEE are similar to those of Soxhlet extraction SE . The quality of oil by MUAAEE is superior to that of oil by SE. SEM reveals that MUAAEE facilitates the oil release by damaging the cell structure.
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S0021967320306580
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A reliable and sensitive analytical approach has been optimized for the extraction of seven polychlorinated biphenyls from human breast milk . Hollow fiber liquid phase microextraction was applied for the first time for the extraction and pre concentration of the analytes . Analytes were separated by gas chromatography with electron capture detector for the sensitive detection and mass spectrometry for the unequivocal identification . A rotable central composite design was performed for the multivariate optimization of the method . The best results were obtained at 40C during 30min and 600rpm of stirring speed using a hollow fiber length of 5cm and toluene as an extractant phase and salt addition was not required . The detection limits were in the range 714ng
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A HF LPME method was developed for the determination of PCBs in human breast milk. The HF LPME method is very simple since a sample preparation step is not required. A multivariate design RCCD was applied to optimize the extraction conditions. Extraction time temperature and length of the fiber were main experimental factors. The proposed approach provides limits of detection in the range of 714 ngL
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S0021967320306592
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A method is described for the functionalization of magnetic carbon nanotubes to recognize aristolochic acid and . 3 Glycidyloxypropyltrimethoxysilane was used as a coupling agent to immobilize adenine on a solid support . The morphology and structure of adenine coated magnetic carbon nanotubes was investigated using transmission electron microscopy scanning electron microscopy X ray diffraction and a vibrating sample magnetometer . The adsorption performance of the adenine coated magnetic carbon nanotubes was evaluated via adsorption isotherms the kinetics and selectivity tests . The adsorption capacity of the adenine functionalized sorbent for aristolochic acid was determined to be 24.5g mg
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A novel magnetic nanocomposite was designed and synthesized by using adenine. Adenine was used to provide adsorption site based on multiple interactions. The magnetic nanocomposite can selectively recognize aristolochic acids. The nanocomposite was exploited to extract aristolochic acids from TCMs.
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S0021967320306609
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The potential of Micellar Electrokinetic Chromatography to achieve enantiomeric separations is reviewed in this article . The separation principles and the most frequently employed separation strategies to achieve chiral separations by Micellar Electrokinetic Chromatography are described . The use of chiral micellar systems alone or combined with other micellar systems or chiral selectors as well as of mixtures of achiral micellar systems with chiral selectors is discussed together with the effect of different additives present in the separation medium . Indirect methods based on the derivatization of analytes with chiral derivatizing reagents and the use of achiral micelles are also considered . Preconcentration techniques employed to improve sensitivity and the main approaches developed to facilitate the coupling with Mass Spectrometry are included . The most recent and relevant methodologies developed by chiral Micellar Electrokinetic Chromatography and their applications in different fields are presented .
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The potential of MEKC in the field of chiral separations is reviewed. Separation principles and fundamentals of chiral MEKC are described. Separation strategies employed in chiral MEKC are summarized. Characteristics of the chiral methodologies developed are depicted. The most recent and relevant applications of chiral MEKC are discussed.
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S0021967320306610
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More and more various chemical media are being applied in enantioseparation among them ionic liquids have attracted the long term attention in this decade as green designable solvents . This paper provides comprehensive overview for the applications of ILs in chiral extraction gas chromatography liquid chromatography capillary electrophoresis and other techniques for enantioseparation . Additionally the important resolution mechanisms based on ILs have also been summarized and discussed . This review focuses on the latest development of enantioseparation methods by using ILs in various modes leading to meaningful and valuable information to related fields and thus promotes further research and application of reported methods .
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It is the first review only for ILs in all round enantioseparation ways. Comprehensive literature summary and analysis are carried out in this review. Resolution mechanisms existing problems suggestions and forecast were summarized.
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S0021967320306622
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In this study the microcrystalline cellulose metal organic framework 199 hybrid was applied as sorbent for the dispersive micro solid phase extraction of chlorophenols . The D SPE method combined with high performance liquid chromatography ultraviolet detection was employed to determine of four chlorophenols including 2 chlorophenol 4 chlorophenol 2 3 dichlorophenol and 2 5 dichlorophenol in aqueous . The main parameters of the D SPE process that influence the extraction were investigated and optimized . Based on the outputs the presence of MCC on the surface of MOF 199 leads to improve the properties of MOF 199 and the MCC MOF 199 has the highest sorption capacity durability and porosity in comparison with MCC and MOF 199 . According to the validation study at the optimized conditions the linearity for the analytes was achieved in the range from 0.1 to 200 ng mL
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Microcrystalline cellulose metal organic framework 199 hybrid was synthesized. MCC MOF 199 was used as D SPE adsorbent for the extraction of CPs. The synthesized sorbent exhibited better extraction efficiency than other sorbents. The developed method provided high recovery low LODs and wide linear range.
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S0021967320306634
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A simple and efficient magnetic solid phase extraction method was established with magnetic covalent organic framework as adsorbent to enrich organophosphorus pesticides from fatty milk samples followed by the sensitive determination via LC MS MS . The key parameters influencing the MSPE efficiency were comprehensively investigated to afford an optimized procedure . All the target analytes could be captured directly by magnetic COF from milk without protein precipitation making the pretreatment rapid and convenient . Systematic method validation demonstrated its satisfactory linearity recoveries and precision . The method limits of quantification were 0.2 0.5 g L
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MSPE based on magnetic COF DtTb was presented for the analysis of OPPs in fatty milk. Adsorption mechanisms were demonstrated based on FT IR and XPS analysis. The established method without protein precipitation was simple rapid and efficient. Systematic validation proved its high sensitivity and potential application prospect.
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S0021967320306658
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The reliable measurement of very volatile organic compounds in indoor air by use of thermal desorption gas chromatography in order to include them into evaluation schemes for building products even nowadays is a great challenge . For capturing these small molecules with carbon numbers ranging from C
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Procedure for validation of adsorbents for VVOC sampling. Determination of recovery rates of a complex VVOC gas mixture in the sub ppb range. Investigation of impact of relative humidity on sampling and analysis by TD GC MS. Identification of suitable adsorbent combinations comparison with commercial one.
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S002196732030666X
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A dispersive solid phase extraction method was combined with deep eutectic solventbased solidification of floating organic dropdispersive liquidliquid microextraction and used for the extraction preconcentration of some organophosphorus pesticides residues from edible oil samples . The extracted analytes were quantified with gas chromatographynitrogen phosphorous detector . In this procedure the sample lipids are saponified with a sodium hydroxide solution and then the analytes are adsorbed onto a primary secondary amine sorbent . After that the analytes are desorbed with acetone as an elution dispersive solvent and mixed with choline chloride 3 3dimethyl butyric acid deep eutectic solvent and the mixture is rapidly dispersed into deionized water . Then the obtained cloudy solution is centrifuged and placed into an ice bath . The extraction solvent is solidified on the top of the solution . Finally it is removed and dissolved in acetonitrile and 1 L of the solution is injected into the separation system . Validation of the method showed that limits of detection and quantification were in the ranges of 0.060.24 and 0.200.56 ng mL
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DSPE combined with deep eutectic solventbased SFO DLLME has been developed. GC NPD system was used for quantification of the analytes. The method was applied to determine OPPs in edible oils. Simplicity low cost less toxicity and effective sample preparation are advantages of the method.
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S0021967320306671
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In this study a three phase laminar flow microfluidic chip combined with HPLC was developed for monitoring free and total concentrations of paclitaxel in blood simultaneously . A diluted whole blood sample was introduced into the chip ethyl acetate was introduced into the chip for extraction and an interphase was used to prevent the blood sample from coming into direct contact with the organic phase . Because only free drug can quantitatively diffuse into the organic extraction phase and the free drug fraction has a linear relationship with the dilution factor of blood both the free and total drug concentrations can be obtained by detecting the concentration of paclitaxel in the organic extraction phase . The governing factor such as flow rate for extraction was optimized . Docetaxel was used as an internal standard . The reliability of the quantitative diffusion of molecules in the TPL chip was proved by the methodological investigation of PTX in PBS sample which showed a good linearity in the concentration range of 0.5 100g mL and a detection limit of 7ng mL . Good repeatibilities for retention time RSD of PTX is 1.23 docetaxel is 1.14
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A rapid simple and low cost simultaneous determination of free and total PTX blood drug concentration. An integration of free drug extraction from whole blood using a three phase microfluidic chip without centrifugation. A linear relationship between the dilution factor and the free drug fraction in blood was found and established.
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S0021967320306683
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Two sets of polystyrene nanoparticles with comparable core sizes but different carboxyl group densities were made and separated using asymmetric flow field flow fractionation capillary electrophoresis and the off line hyphenation of both methods . Our results revealed the significant potential of two dimensional off line AF4 CE hyphenation to improve the separation and demonstrated for the first time the applicability of CE to determine the functional group density of nanoparticles . Compared to the result acquired with conductometric titration the result obtained with synthesized 100nm sized PSNPs revealed only a slight deviation of 1.7 . Commercial 100nm sized PSNPs yielded a deviation of 4.6 . For 60nm sized PSNPs a larger deviation of 10.6 between both methods was observed which is attributed to the lower separation resolution .
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PS NPs with tuned COOH group densities were separated by CE and CE AF4 hyphenation. AF4 CE hyphenation led to a significant improvement in the separation resolution. CE calibration was performed using custom made COOH functionalized PS NPs. This enabled quantification of the functional group density of commercial NP.
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S0021967320306695
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The selective extraction and column separation rear earth elements were investigated in the present work . Herein the functional ligand of N N dioctyldiglycolic acid was synthesized and chemically grafted on the silica gel particles to give the novel material
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Novel solid phase extraction material for extracting rare earth elements REEs . Good adsorption capacity high efficiency with rapid adsorption kinetics within 100min and significant adsorption capacity 126.33mg g . Applied for preliminary separation of REEs.
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S0021967320306701
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The early identification of unstable glass objects in museum collections is essential for their conservation but as yet can not be accomplished straightforwardly . Accordingly this paper describes the development and validation of a simple protocol for quantitative determination of ions characteristic of the chemical decay of historic glass using surface swabbing combined with ion exchange chromatography . The establishment of a robust protocol is an important step in the development of an early warning system for the chemical deterioration of unstable glass . Using a model system the protocol was validated for specificity linearity accuracy precision limits of detection and limits of quantification for 10 anionic species and 6 cationic species . Good validation parameters R
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A sampling protocol for the study of unstable historic glass was established. Ion Chromatography was used for analysis for determination of glass sickness. Good validation parameters were obtained for ions related to glass degradation. The protocol is promising for an early warning system for unstable glass in museums
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S0021967320306713
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Nowadays enantioseparation of racemic pharmaceuticals in preparations is a prime concern by drug authorities across the globe . In the present work it was attempted to develop novel enantioselective extraction method for five clinicallyused drugs as racemates . The enantioselective solid liquid extraction of these racemic drugs was carried out successfully by the use of chiral ionic liquid in combination with a metal organic framework for the first time . The composite
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New composite separation material of. was prepared and characterized. Enantioselective extraction was developed using. for the first time. CIL was used in developing agent of TLC for enantioseparation for the first time. Good results were achieved for various racemates by dispersive biphase extraction.
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S0021967320306725
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Comprehensive two dimensional gas chromatography based on flow modulation is gaining increasing attention as an alternative to thermal modulation the recognized GCGC benchmark thanks to its lower operational cost and rugged performance . An accessible rational procedure to perform method translation between the two platforms would be highly valuable to facilitate compatibility and consequently extend the flexibility and applicability of GCGC . To enable an effective transfer the methodology needs to ensure preservation of the elution pattern separation power and sensitivity . Here a loop type thermal modulation system with dual detection used for the targeted analysis of allergens in fragrances is selected as reference method . Initially six different columns configurations are systematically evaluated for the flow modulated counterpart . The set up providing the most consistent chromatographic separation 20m x 0.18mm
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matching chromatographic performances between thermal and flow modulated GCGC. intuitive method translation procedure between thermal and flow modulated GCGC. exploring column configuration flexibility and performances in flow modulated GCGC. allergens profiling methods equivalence for sensitivity linearity and accuracy.
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S0021967320306737
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A new and sensitive analytical method for the simultaneous determination of secondary lipid peroxidation aldehydes has been successfully developed and validated . Malondialdehyde acrolein formaldehyde acetaldehyde propanal and pentanal were extracted and derivatized using 2 4 dinitrophenylhydrazine by gas diffusion microextraction combined with dispersive liquid liquid microextraction for gas chromatography mass spectrometry analysis . The experimental conditions have been optimized by experimental designs . The analytical method validation in accordance to the Food and Drug Administration guidance provided good results in terms of linearity with r
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The first gas diffusion microextraction combined with dispersive liquid liquid microextraction for analysis of lipid peroxidation aldehydes. Occurrence of lipid peroxidation aldehydes in edible oil samples was characterized by GCMS analysis. The highest contents of malondialdehyde were found in pomace olive oil. Acrolein and propanal were quantified in all the samples. Lipid peroxidation aldehydes showed potential to be used as food quality markers.
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S0021967320306762
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In this work a single cross linking functional monomer 2 5 divinylterephthalaldehyde was designed and synthesized to simplify the preparation of molecularly imprinted polymers . In the presence of estradiol as a template MIPs were successfully prepared using 2 5 divinylterephthalaldehyde along with a solvent and initiator . This method reduced most of the complex variables encountered in the traditional synthesis . Characterization of the morphology and structure of the MIPs was performed by scanning electron microscopy Fourier transform infrared spectroscopy and Brunauer Emmett Teller analysis . Compared with non imprinted polymers the MIPs had higher adsorption capacities for five estrogens with imprinting factors above 2.9 . The MIPs had high extraction efficiencies good functional properties long lifetimes and good reproducibility which made them suitable for solid phase microextraction . Coupled with ultra high performance liquid chromatography tandem mass spectrometry the MIP based fibers were applied to SPME for the analysis of five estrogens in milk samples . Under the best conditions the established method had a wide linear range 0.510000 ng kg
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A single cross linking monomer was synthesized for making MIPs for estrogens. The MIPs SPME fiber was prepared with remarkable recognition properties. The proposed MIPs SPME method exhibited low limits of detection. The fiber was employed for the analysis of estrogens in real milk samples.
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S0021967320306774
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Tile based Fisher ratio analysis has recently been developed and validated for discovery based studies of highly complex data collected using comprehensive two dimensional gas chromatography coupled with time of flight mass spectrometry . In previous studies interpretation and utilization of F ratio hit lists has relied upon manual decomposition and quantification performed by chemometric methods such as parallel factor analysis or via manual translation of the F ratio hit list information to peak table quantitative information provided by the instrument software . Both of these quantification approaches are bottlenecks in the overall workflow . In order to address this issue a more automatable approach to provide accurate relative quantification for F ratio analyses was investigated based upon the mass spectral selectivity provided via the F ratio spectral output . Diesel fuel spiked with 15 analytes at four concentration levels produced three sets of two class comparisons that were submitted to tile based F ratio analysis to obtain three hit lists with an F ratio spectrum for each hit . A novel algorithm which calculates the signal ratio between two classes was applied to all mass channels
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Information in Fisher ratio hit lists is used to estimate analyte concentration ratio. An automatable approach for relative quantification is investigated and validated. Lack of fit combined with p value thresholds indicate mass channel. selectivity. Isolation of pure. is achieved without higher level signal decomposition algorithms. The. that produced the highest Fisher ratio was generally the purest
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S0021967320306786
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Surfactants are used in various applications cosmetics pharmaceuticals petrochemicals environmental etc . Many of these compounds are polydisperse and because of this intrinsic polydispersity it is essential to have a universal detector with a uniform response to quantify them in a simple way . Indeed Charged Aerosol Detector was presented as a universal detector with a uniform response . Thus in the present study the CAD response in a High Performance Liquid Chromatography CAD configuration HPLC
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HLIC CAD analysis of alcohol ethoxylated surfactants. Isolation of homologues by semipreparative separation. Determination of response factor of homologues. Unexpected very different response factors.
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S0021967320306798
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Dopamine is a catecholamine neurotransmitter that degrades rapidly in aqueous solutions hence its analysis following brain microdialysis is challenging . The aim of the current study was to develop and validate a new microdialysis coupled LC MS MS system with improved accuracy precision simplicity and turnaround time for dopamine serotonin methamphetamine amphetamine 4 hydroxymethamphetamine and 4 hydroxyamphetamine analysis in the brain . Dopamine degradation was studied with different stabilizing agents under different storage conditions . The modified microdialysis system was tested in vitro and was optimized for best probe recovery assessed by gain . LC MS MS assay was developed and validated for the targeted compounds . Stabilizing agents as well as internal and cold standards were added on line to the dialysate flow . Assay linearity range was 0.01100ng mL precision and accuracy passed criteria and LOQ and LLOQ were 0.2 and 1.0 pg respectively . The new microdialysis coupled LC MS MS system was used in Wistar rats striatum after 4mg kg subcutaneous methamphetamine . Methamphetamine rapidly distributed to rat striatum reaching an average 200ng mL maximum 82.5min post dose . Amphetamine followed by 4 hydroxymethamphetamine was the most abundant metabolite . Dopamine was released following methamphetamine injection while serotonin was not altered . In conclusion we proposed and tested an innovative and simplified solution to improve stability accuracy and turnover time to monitor unstable molecules such as dopamine by microdialysis .
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A new microdialysis LCMS system was developed and optimized for dopamine stability. Stabilizers standards were added on line to improve LCMS quantitative results. Rat striatal dopamine was increased by 7 fold post methamphetamine 4mg kg sc dose. Serotonin methamphetamine and its metabolites were concurrently quantified. The new method was accurate and precise 15 with good probe recovery 37 .
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S0021967320306890
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Innovations in extraction phases extraction modes and hyphenated instrument configurations are the most important issues to address for progress in the solid phase microextraction methodology . In this regard we have embarked on the development of a novel biocompatible 96 monolithic inorganic hollow fiber array as a new configuration for high throughput SPME on a 96 well plate system . An arrangement of highly ordered 96 titania Hydroxyapatite TiO
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An innovative configuration was developed for high throughput SPME approach. A new design inorganic HAP TiO. hollow fiber with PVA modification was introduced. Doxorubicin quantification by SPME was reported for the first time in urine media. Biocompatibility of sorbent offers multi target monitoring in biological matrices. Better method validation data were obtained in comparison with related techniques.
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S0021967320306907
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Various techniques have been evaluated for the extraction and cleanup of pesticides from environmental samples . In this work a Selective Pressurized Liquid Extraction method for pesticides was developed using a Thermo Fisher Scientific Accelerated Solvent Extraction system . This instrument was compared to the newly introduced extraction instrument the Energized Dispersive Guided Extraction system which combines Pressurized Liquid Extraction and dispersive Solid Phase Extraction . We first optimized the SPLE method using the ASE instrument for pesticide extraction from alfalfa leaves using layers of Florisil and graphitized carbon black downstream of the leaf homogenate in the extraction cell . We then compared results obtained for alfalfa and citrus leaves with the Layered ASE method to those from a method in which the leaf homogenate and sorbents were mixed and to similar methods modified for use with EDGE . The ASE and EDGE methods led to clear colorless extracts with low residual lipid weight . No significant differences in residual lipid masses were observed between the methods . The UV Vis spectra showed that Florisil removed a significant quantity of the light absorbing chemicals but that GCB was required to produce colorless extracts . Recoveries of spiked analytes into leaf homogenates were generally similar among methods but in several cases significantly higher recoveries were observed in ASE extracts . Nonetheless no significant differences were observed among pesticide concentrations in field samples when calculated with the isotope dilution method in which labelled surrogates were added to samples before extraction . The extraction time with the ASE methods was 45 minutes which was 4.5 times longer than with the EDGE methods . The EDGE methods used 10 mL more solvent than the ASE methods . Based on these results the EDGE is an acceptable extraction instrument and for most compounds the EDGE had a similar extraction efficiency to the ASE methods .
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An Accelerated Solvent Extraction ASE method for 20 pesticides was developed. An Energized Dispersive Guided Extraction EDGE method was compared. ASE and EDGE methods were used to extract pesticides from citrus and alfalfa leaves. The ASE and EDGE instruments had comparable extraction efficiency. The EDGE instrument extracted samples 4.5 times faster than the ASE instrument.
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S0021967320306920
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Animal feeds are often reported to be contaminated with chemical residues and when present above the maximum legal limit these compounds can cause harmful effects to consumers of animal produce . Thus animal feed safety is an important regulatory concern . The aim of this study was to optimise a multiresidue method for the simultaneous analysis of multi class pesticides and a number of frequently used veterinary drugs using LC MS MS and GCMS MS . The method was validated in a range of feed matrices including maize feed poultry feed and mixed feed concentrate . The optimised sample preparation workflow involved extraction of feeds with ethyl acetate followed by a freezing step used for eliminating the matrix co extractives . The extract was further cleaned by dispersive solid phase extraction with a combination of primary secondary amine C18 and florisil sorbents . From the cleaned extract an aliquot was analysed by GCMS MS while another portion of it was solvent exchanged to acetonitrile water and then analysed by LC MS MS . This method effectively minimised the matrix interferences . A total of 192 pesticides was analysed by GCMS MS within a runtime of 22min . The LC MS MS method was validated for 187 compounds including 17 veterinary drugs . For most of the compounds the limit of quantification was 0.01mg kg . The recoveries at LOQ and higher levels ranged between 70 and 120 with precision RSDs of 20 . The method provided a precise analysis in a wide range of market feed samples . As shown the method is suitable for regulatory and commercial testing purposes .
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A multiresidue method for large scale analysis of pesticides veterinary drugs in feed is reported. Selective residue analysis by GCMS MS 192 compounds LC MS MS 187 compounds . High accuracy precision in analysis at 0.01mg kg and higher residue levels. The method was validated in a wide variety of feed matrices with diverse compositions. It provided precise analysis of incurred residues in feed matrices.
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S0021967320306968
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Monitoring preparative protein chromatographic steps by in line spectroscopic tools or fraction analytics results in medium or large sized data matrices . Multivariate Curve Resolution serve to compute or to estimate the concentration values of the pure components only from these data matrices . However MCR methods often suffer from an inherent solution ambiguity which underlies the factorization problem . The typical unimodality of the chromatographic profiles of pure components can support the chemometric analysis . Here we present the pure components estimation process within the framework of the area of feasible solutions which is a systematic approach to represent the range of all possible solutions . The unimodality constraint in combination with Pareto optimization is shown to be an effective method for the pure component calculation . Applications are presented for chromatograms on a model protein mixture containing ribonuclease A cytochrome c and lysozyme and on a two dimensional chromatographic separation of a monoclonal antibody from its aggregate species . The root mean squared errors of the first case study are 0.0373 0.0529 and 0.0380 g L compared to traditional off line analytics . The second case study illustrates the potential of recovering hidden components with MCR from off line reference analytics .
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Calibration free mathematical approach for analyzing preparative protein chromatograms. Application to multivariate UV Vis chromatograms of a mixture of model proteins. Application to chromatograms from off line reference analytics for a mAb and its impurities. Based on a state of the art multivariate curve resolution technique with unimodality constraint. The influence of solution ambiguities of the multivariate curve resolution approach is analyzed.
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S002196732030697X
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Herein we present an efficient column switching method that relies on a custom made T union passive diffusion micromixer to assist water dilution and promote trap solute focusing of a high sample volume dissolved in pure organic solvent using a 0.075mm i.d . nano LC column . This method allows injecting 20 L of sample volume speeding up the analysis time with a 400 fold increase of the limits of quantitation for selected compounds . Five pesticides in different media were used as model compounds and the analyses were carried out with a triple quadrupole mass spectrometer equipped with a Liquid Electron Ionization LC MS interface working in multiple reaction monitoring mode . The system microfluidics were investigated using COMSOL modeling software . Robustness of the entire system was evaluated using a post extraction addition soil extracts with limits of detection values spanning from 0.10 to 0.45g L. Reproducible results in terms of peak area peak shape and retention times were achieved in soil matrix . Repeatability test on peak area variations were lower than 10 .
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Nano HPLC is particularly suitable for coupling with mass spectrometry. Water sample dilution and pre concentration trap can increase injection volumes. LC EI MS is useful in targeted and non targeted analysis. LC EI MS is not affected by matrix effects typical of API sources. Microfluidic passive micromixer allows dilution of sample in strong eluting solvent.
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S0021967320306981
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Sialylation an important form of glycosylation is involved in many biological processes and plays an important role in the development of diseases . However due to the low abundance among various glycosylation and lack of efficient enrichment method with high specificity the study of sialylation remains a challenge . Herein multi histidine modified microspheres were synthesized to enrich sialylated glycopeptides . It was found that MHM could selectively enrich sialylated glycopeptides from over 100 times of non sialylated glycopeptides which indicated MHM possessed good enrichment specificity towards sialylated glycopeptides . Furthermore MHM were utilized to the large scale analysis of protein sialylation and 510 intact glycopeptides were identified with over 94.5 sialylated glycopeptide specificity from 4 L human serum . The good specificity could be attributed to the synergistic effect by the electrostatic interaction and hydrophilic interaction . Hence MHM could provide an alternative approach for the analysis of site specific sialylation at proteome level from complex biological samples .
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We prepared a multiple histidine modified microspheres MHM to specifically enrich sialylated glycopeptides. Sialylated glycopeptides could be enriched with MHM by electrostatic interaction hydrophilic interaction and synergistic effect. MHM can enrich 510 intact glycopeptides from 4 L human serum with over 94.5 specificity in triple replicates.
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S0021967320307007
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Block copolymers that exhibit both an upper critical solution temperature and a lower critical solution temperature are difficult to characterize due to inherent solubility difference between the two blocks . For example accurate determination of both the molar mass and molar mass distribution is challenging for polyzwitterion
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Size exclusion chromatography of poly zwitterion. isopropyl acrylamide . Successful characterization of molar mass and molar mass distribution. 0.2M KI in water Agilent PolarGel columns. 0.2M KI 30 DMF in water Agilent PolarGel and Tosoh TSKgel columns. Eluents circumvent typical issues of characterizing zwitterionic copolymers.
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S0021967320307019
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A new broadly applicable achiral chiral 2 dimensional heart cutting platform is designed comprising a multi column selection approach in the chiral dimension . As both dimensions are operated in a highly aqueous reversed phase type mode analysis of a broad range of pharmaceutical solutes Log
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A 2D LC platform is developed for chiral analysis of pharmaceuticals. D on column peak focusing appears feasible for larger 500L sample loops. D breakthrough issues and significant peak broadening phenomena are absent. An automated chiral screening is accomplished via six chiral columns. Via hybrid HiRes chiral impurities are detected down to 0.05 level.
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S0021967320307020
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Selecting the appropriate solvent system is the key to the successful separation of samples by using countercurrent chromatography . Although high speed countercurrent chromatography has been widely used in the separation and preparation of natural products the selection of a solvent system has always been a stumbling block to the application of high speed countercurrent chromatography . In order to explore a rapid and practical prediction method to select countercurrent chromatography solvent system five linear prediction models of the Arizona solvent system family was established by using fourteen compounds with different structures and five HPLC columns of different brands . And two different solvent system selection methods The partition coefficient
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A rapid and practical solvent system prediction method was established. 14 compounds and 5 HPLC columns were used to establish the prediction method. 5 compounds and 2 Chinese herbal extracts were used to verify the prediction method. The method simplifies the selection process of HSCCC solvent system obviously.
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S0021967320307032
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The physicochemical properties of small molecules that can be determined by retention measurements in reversed phase liquid chromatography include solvent based properties inferred from equilibrium processes occurring predominantly in the mobile phase and sorption properties for materials which can be used as stationary phases inferred from solute stationary phase interactions . In addition physicochemical properties can be estimated from correlation models based on surrogate chromatographic systems with a similar capability for intermolecular interactions to the chemical or biological system . Examples of properties determined by direct methods include molecular descriptors acid dissociation constants formation constants and surface properties of solids determined by inverse liquid chromatography . Examples of properties estimated by indirect methods include hydrophobicity lipophilicity n octanol water partition constant soil water sorption constant non specific toxicity to fish and microorganisms and permeation coefficients for the blood brain and skin water barriers . Since all approaches depend on an accurate measurement of chromatographic retention parameters typical operational and mechanistic problems are discussed from the perspective of data quality . Fundamentally the accuracy of direct methods is limited by stationary phase heterogeneity and indirect methods by the limited number of suitable surrogate chromatographic models .
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Direct methods for the prediction of equilibrium constants. Main limitation of direct methods is the heterogeneity of the retention mechanism. Indirect methods in the form of correlation models are the most common. The paucity of surrogate chromatographic models is the main limitation of indirect methods. Statistical parameters discussed for model selection and predictive capability.
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S0021967320307056
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Recent studies have shown that by combining orthogonal non affinity chromatography steps it is possible to rapidly develop efficient purification processes for molecules of interest . Here we build upon previous work to develop a flexible framework for identifying resins that remove optimally orthogonal sets of impurities for a wide variety of products . Our approach involves screening a library of proteins with diverse properties on a library of resins and quantifying each resins ability to separate every protein pair in the library . Orthogonality is then defined as the degree to which two resins separate mutually exclusive sets of protein pairs . We applied this approach to a library of model proteins and a series of strong salt tolerant and multimodal ion exchangers and evaluated which resin combinations performed well and which performed poorly . In particular we found that strong cation and strong anion exchangers were orthogonal while strong and salt tolerant anion exchangers were not orthogonal . Interestingly salt tolerant and multimodal cation exchangers were found to be orthogonal and the best resin combination included a multimodal cation exchange resin and a tentacular anion exchange resin . This approach for quantifying orthogonality is valuable in that it can be used both as a criteria for resin design as well as process design . We envision that using this framework it will be possible to design a set of next generation chromatography ligands that are explicitly engineered to optimize separability and orthogonality .
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Developed a framework to identify resins that remove orthogonal sets of impurities. Screened protein resin libraries and quantified each resins performance. Cation and anion exchangers were orthogonal. Strong and salt tolerant anion ion exchangers were not orthogonal. Salt tolerant and multimodal cation exchangers were orthogonal. Our framework facilitates engineering resins to optimize separability orthogonality.
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S0021967320307068
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There is a huge still increasing market for synthetic and therapeutic peptides . Their quality control is commonly based on a generic reversed phase liquid chromatography method with C18 stationary phase and acetonitrile gradient with 0.1 trifluoroacetic acid in the mobile phase . It performs exceptionally well for a wide variety of impurities yet structurally closely related impurities with similar sequences not resolved in preparative RPLC may easily coelute in the corresponding QC run as well . To address this problem an advanced generic 2D LC impurity profiling method was developed in this work . It employs a selective comprehensive RPRP 2D LC separation using a 1002.1mm ID column with the common acidic generic gradient in the first dimension while RPLC under basic pH on a short 303mm ID column is used in the second dimension . Recording data with a UV detector at 215nm after
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Selective comprehensive 2D liquid chromatography for peptide quality control. Main peptide peak from. D RPLC comprehensively sampled into. D for more reliable QC. D RPLC at pH 9 exhibits complementary selectivity to. D RPLC with trifluoroacetic acid. sRPRP 2D LC coupled to multiple detectors UV charged aerosol detector QTOF . Advanced generic sRPRP 2D LC peptide QC employed to Oxytocin analysis using SWATH.
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S002196732030707X
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The separation of the proteins Bovine Serum Albumin and Myoglobin was achieved by Size Exclusion Simulated Moving Bed and performed experimentally in the FlexSMB unit an SMB unit designed and built in the Laboratory of Separation and Reaction Engineering . Before accomplishing the separation experiments in the mentioned unit separation regions were computed by simulation based on a phenomenological mathematical model to determine appropriate operating conditions . The developed model was validated in advance against fixed bed dynamic adsorption experimental results for pure component and binary mixtures . Then the SMB experiments were carried out and purities of the Mb on the extract and BSA on the raffinate streams were 98 and 96 respectively . The achieved recoveries were 80 of Mb on the extract and 94 of BSA on the raffinate . Lastly productivities of 6.4 g
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Bovine serum albumin and myoglobin are separated by size exclusion chromatography. A mathematical model was developed and validated against fixed bed experiments. Simulated moving bed unit performance was predicted by the developed model. Separation regions were computed to determine the operating point. Simulated moving bed experiments were carried out in the FlexSMB unit.
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S0021967320307093
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Atmospheric particulate matter is made up of suspended microscopic solid or liquid materials . It is derived from natural or anthropogenic sources . PM encompasses inhalable coarse particles with aerodynamic diameters of between 2.5m and 10m fine particles and ultrafine particles . In addition to being directly inhalable causing harm PM can also exert adverse effects on human wellbeing and the environment by its impact on precipitation and climate . Moreover chemical contaminants may also be found adsorbed on PM adding another dimension to the hazardous aspects of these materials . PM is normally collected on filters or impactors . PM adsorbed contaminants need to be taken into solution before they can be extracted . This review focuses on a discussion of solvent minimized sample preparation procedures originally developed for aqueous samples for the extraction and preconcentration of primarily organic contaminants from fine and coarse PM .
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Atmospheric particulate matter comprises of coarse fine and ultrafine particles. Particulate matter is normally collected on filters or impactors. Chemical contaminants may be found adsorbed on particulate matter. Contaminants adsorbed on particulate matter are taken into solution before extraction. This review focuses on solvent minimized sample preparation procedures for particulate matter.
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S002196732030710X
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Differing sensitivity is the main obstacle for a direct combination of HPTLC with NMR spectroscopy . A sufficient amount of the isolated compound zone must be provided by HPTLC for subsequent offline NMR detection . To fill the gap a straightforward procedure was developed using the same analytical HPTLC system for both bioprofiling and isolation of bioactive zones from multicomponent mixtures . The HPTLC effect directed analysis revealed several bioactive compounds in five botanical extracts i.e .
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Techniques of different sensitivities were combined to identify quantify bioactive compounds. Identification quantification of bioactive structural isomers in salvia oregano thymus and apple. Good correlation of quantitative results obtained by HPTLC Vis and HPTLC. H qNMR PULCON. Comparison of HPTLC. H qNMR PULCON versus. H deconvoluted versus. C HSQC. Low solvent volume consumed compared to bioactivity guided fractionation.
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S0021967320307111
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We report on the performance of three classes of evolutionary algorithms evolution strategies and covariance matrix adaptation evolution strategy as a means to enhance searches in the method development spaces of 1D and 2D chromatography . After optimisation of the design parameters of the different algorithms they were benchmarked against the performance of a plain grid search . It was found that all three classes significantly outperform the plain grid search especially in terms of the number of search runs needed to achieve a given separation quality . As soon as more than 100 search runs are needed the ES algorithm clearly outperforms the GA and CMA ES algorithms with the latter performing very well for short searches but being susceptible to convergence to local optima for longer searches . It was also found that the performance of the ES and GA algorithms as well as the grid search follow a hyperbolic law in the large search run number limit such that the convergence rate parameter of this hyperbolic function can be used to quantify the difference in required number of search runs for these algorithms . In agreement with one s physical expectations it was also found that the general advantage of the GA and ES algorithms over the grid search as well as their mutual performance differences grow with increasing difficulty of the separation problem .
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Have assessed use of evolutionary algorithms in 1D and 2D LC method development. Have compared 3 algorithm classes and benchmarked them against plain grid search. The optimised evolution strategies ES algorithm is identified as the best performing. Difference between algorithms grows with difficulty of the separation problem.
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S0021967320307123
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In recent years mussel inspired polydopamine based materials have been widely used as stationary phases for open tubular capillary electrochromatography because of their various excellent properties . Nevertheless the traditional synthesis routes of functionalized PDA based capillary columns usually are time consuming and limited in aqueous solutions . Herein we report a facile and rapid route to prepare octadecylamine functionalized PDA coated OT CEC columns in organic solvents via a novel one step in situ solvothermal assisted coating strategy . Through this developed solvothermal assisted approach the growth rate of ODA PDA coating was significantly speeded up and their hybrid coating process on the capillary inner surface could be rapidly completed in 60min . The successful preparation of the solvothermal assisted ODA PDA hybrid coating were systematically characterized and confirmed by several methods . The influence of the preparation parameters on the formation of hybrid coating and the separation ability of the ODA PDA modified columns were systematically explored . Consequently the high efficiency baseline separation of four kinds of neutral acidic and basic analytes were achieved based on the ODA PDA modified columns . The repeatability of the solvothermal assisted ODA PDA coated column was also studied and the relative standard deviations for intra day inter day and column to column were all less than 5 . Additionally the solvothermal assisted ODA PDA modified column exhibited good stability and long lifetime .
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A novel solvothermal assisted coating method for CEC stationary phase was presented. The strategy greatly improve the preparation efficiency of PDA based CEC columns. More stationary phases are expected to be readily prepared via the universal method.
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S0021967320307135
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During stoppers production large amounts of cork by products are generated being used as low value material . This project aims to turn CBPs into smart natural and sustainable materials for solid phase extraction of pesticides from water . The study describes the use of CBPs for the extraction of 17 fungicides followed by gas chromatography tandem mass spectrometry analysis . The most critical parameters affecting SPE were optimized by experimental design methodology . Under the optimal conditions the method was successfully validated in terms of linearity repeatability and intermediate precision . Fungicide recovery was assessed in different real water samples including river fountain rainwater and spring water at 3 concentration levels 0.1 0.5 and 10 g L
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For the first time the use of cork by products CBPs is proposed for fungicide extraction. The most critical parameters affecting SPE were optimized by experimental design. The proposed method was validated for 17 common use fungicides in environmental water. Water samples collected in vineyards revealed the presence of fungicides at g L. CBPs is an efficient low cost green ecofriendly alternative for fungicide analysis.
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S0021967320307147
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A fast simple environmentally friendly and sensitive on line concentration method using microemulsion system as background solution was developed for the trace detection of propazine atrazine simazine in food samples . The electrokinetic injection assisted micelle to cyclodextrin stacking was designed for the enrichment of target compounds . The factors affected enrichment performance such as the kind of CDs the amount of CDs the concentration of methanol in BGS the concentration of micelle in sample matrix the concentration of phosphoric acid in BGS and the sample injection time were optimized . The optimized electrophoretic condition was obtained as following 50 mM CD 20 mM SDS in sample matrix . 80 mM PA and 20 MeOH in BGS sample solution by electrokinetic injection at 10 kV for 80 s. Under the optimized conditions described above the linear range was 0.120 ug mL with a good linear relationship with a correlation coefficient 0.9985 . The SEFs for the propazine atrazine simazine were found to be 123 85 and 62 respectively . The proposed MCDS MEEKC method provided an efficient method for trace analysis of triazine herbicides in honey and
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An on line concentration method MCDS MEEKC was developed for analysis of triazine herbicides. Electrokinetic injection assisted micelle to cyclodextrin stacking is applied. The developed method is successfully used for the honey and. samples. The sensitivity enrichment of triazine herbicides are 62 123 fold compared with the conventional CE method.
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S0021967320307159
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Numerous structurally different amides and imides including succinimide derivatives exhibit diverse bioactive potential . The development of new compounds requires rationalization in the design in order to provide structural changes that guarantee favorable physico chemical properties pharmacological activity and safety . In the present research a comprehensive study with comparison of the chromatographic lipophilicity and other physico chemical properties of five groups of 1 arylsuccinimide derivatives was conducted . The chemometric analysis of their physico chemical properties was carried out by using unsupervised and supervised pattern recognition methods while the correlations between the
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QSRR analysis of retention behavior of five series of 1 arylsuccinimide derivatives was done. Comparative chemometric analysis of their chromatographic lipophilicity was carried out. Discriminant analysis of the compounds based on chromatographic lipophilicity was performed. High quality linear and non linear QSRR models were established.
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S0021967320307160
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A selective and highly sensitive high performance liquid chromatography with fluorescence derivatization method was developed for determination of ethinyl estradiol one of endocrine disrupting compounds . The fluorescence derivatization procedure was based on Sonogashira coupling reaction using 4 4 5 diphenyl 1
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DIB I was used for selective derivatization of EE. Sonogashira coupling reaction. Various experimental parameters were examined after that the fluorescent product was separated using HPLC FL system. The method is selective precise robust and sensitive LOD 7.4 ng L. and it was applied to monitor EE in river water samples.
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S0021967320307184
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An analytical method for the quantification of thirty three perfluoroalkyl and polyfluoroalkyl substances in animal liver was developed applying the isotopic dilution methodology with twenty one labelled isotopologues of native compounds . The proposed protocol involved the determination of short and long aliphatic chain PFASs C
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A method for 33 PFASs was developed in liver using LC Q Orbitrap. Satisfactory performance characteristics were obtained. LOQs were generally lower than 100 pg. Method was employed for the analysis of farm animal liver samples. Chicken was the less contaminated species.
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S0021967320307202
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The effect of bead and ligand structure on protein adsorption was investigated for multimodal anion exchangers combining a quaternary ammonium ion group with hydrophobic moieties Nuvia aPrime 1 and aPrime 2 based on a 54 m diameter polymeric bead and Capto Adhere ImpRes and Capto Adhere based on agarose beads 51 and 78 m diameter respectively . Bovine serum albumin monomer BSA dimer and thyroglobulin were used as model proteins . Based on TEM imaging and iSEC the Nuvia resins have a microgranular structure and large pores while the Capto resins have a fibrous structure and smaller pores . Comparable binding capacities decreasing as salt is added are observed for all three proteins on the Nuvia resins . Higher capacities also decreasing as salt is added are observed for BSA monomer and dimer on the Capto resins . However the Tg binding capacity is very low in this case and increases as salt is added . Confocal laser scanning microscopy show that the kinetics are controlled by pore diffusion for all four resins but with diffusivities that decrease as the protein size increases especially for the Capto resins . For Tg at low salt binding is restricted to a thin shell close to the bead surface for both Capto resins . The ratio of effective and free diffusivity is about 0.30 0.18 and 0.08 for BSA monomer BSA dimer and Tg respectively on the Nuvia resin . These values decrease to about 0.11 0.04 and 0.01 respectively for the Capto resins as a result of diffusional hindrance . Dynamic binding capacities are consistent with the equilibrium and rate behaviors .
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Structural and adsorptive properties of multimodal anion exchangers are characterized. Adsorption rates are controlled by pore diffusion. Mass transfer of large proteins is highly restricted in agarose based resins. Polymer based resins provide higher dynamic binding capacity at short residence times
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S0021967320307214
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Anabolic androgenic steroids have been the most commonly abused substances taken by not only professional sportsmen but also recreational bodybuilders . The detection of micro dose testosterone misuse is particularly challenging as it possesses pseudo endogenous origin and is sometimes impossible to be identified in urine samples . Dried blood obtained by finger pricking has been proven to be an alternative matrix for better correlating to physiological responses . Moreover the introduction of the volumetric absorptive microsampling technology allows overcoming some major limitations of spotting blood onto a filter paper card . In this work a fast and sensitive GC MS MS method was developed and validated for the quantification of AAS in DB collected by means of VAMS . T and the eight top abused synthetic AAS namely nandrolone boldenone mesterolone drostanolone metenolone metandienone oxandrolone and dehydrochloromethyl T were selected as the target analytes . The method based on VAMS exhibited good precision accuracy as well as stability and superior extraction recoveries over the punched DB spots reported in the literature . The chromatographic separation was achieved within 6.4 min and the detection limit is as little as 50 fg i.e . able to detect 0.10 ng mL
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Nine anabolic steroids are separated within 6.4 min and are detectable at 50 fg. VAMS dried blood exhibits good stability and better recovery over spotting card. Quantification of testosterone between serum and VAMS dried blood is in agreement. Doping with micro dose testosterone can be caught by using 20 L of dried blood.
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S0021967320307226
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Ionic liquids as tuneable highly soluble non flammable non volatile and reusable extractants have attracted extensive attention in the extraction of flavonoids from plants . In the present work novel dual chain imidazolium derived ionic liquids were synthesized by a simple and efficient method and characterized . Then the imidazolium ionic liquids with different cation were used in the microwave assisted extraction of flavonoids from
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Novel dual chain ionic liquids have been synthesized by an improved way. Bmbim Br with high extraction efficiency has been found. The extraction selectivity of flavonoids by ionic liquids was studied.
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S0021967320307238
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Waterfowl populations have been decreasing in Europe for the last years and pollution appears to be one of the main factors . This study was conducted to develop a single sensitive and robust analytical method for the monitoring of 2 fungicides 15 herbicides 3 insecticides and 24 transformation products in wild bird eggs . One of the major challenges addressed was the characterization of chemicals with large logP range . A total of 11 different extraction parameters were tested in triplicate to optimize the extraction protocol on generic parameters buffer addition and use of clean up steps . Quantification was based on matrix match approach with hen eggs as reference matrix . Particular attention was payed to matrix effects quantification limits 0.5 to 25ng.g
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Development of a multi residue analysis method for 44 pesticides and TP in eggs. Six critical parameters of the sample extraction protocol were fully studied. Extraction recoveries were superior to 50 even for the most polar TP. Inter day precision relative standard deviations were inferior to 22 at LOQ.
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S002196732030724X
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During a screening of cyclodextrins as chiral selectors for the separation of daclatasvir and its enantiomer by capillary electrophoresis an unusual phenomenon for CDs was observed that is two peaks with a plateau in between using CD as chiral selector . The same result was encountered when enantiopure DCV was injected or when analyzing a sample containing enantiopure DCV and CD in a CD free background electrolyte . Peak coalescence was observed at 45C and at a pH above 3.5 . Two peaks with a plateau were also observed for DCV stereoisomers as well as a structural analog . However only a single peak was detected if one or both amino acid moieties of DCV were lacking . Nuclear magnetic resonance experiments including Nuclear Overhauser effect based methods showed that in solution DCV adopted a folded conformation in which the isopropyl side chain of the valine residues pointed toward the aromatic rings of DCV . Moreover NMR unequivocally demonstrated the simultaneous formation of DCV CD inclusion complexes with 1 1 and 2 1 stoichiometry which was corroborated by mass spectrometry . In both complexes DCV also adopted a folded structure . The RSSR diastereomer of DCV as well as an analog lacking one of the amino acid moieties also formed 1 1 and 2 1 complexes with CD although a plateau was only observed in the case of the RSSR diastereomer . As shown by CE MS both DCV CD complexes surprisingly comigrated as the first peak while the second migrating peak represents non complexed DCV .
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Simultaneous formation of 1 1 and 2 1 complexes between cyclodextrin and daclatasvir. Unprecedented electrophoretic migration behavior of complexes and free daclatasvir. Analysis of complexes in selector free electrolyte due to high stability. Elucidation of complex structures by NMR spectroscopy.
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S0021967320307251
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This paper reported a new method for the determination of the water distribution in sludge . It was based on a multiple headspace extraction procedure to step wise remove the water vapor from a closed vial containing a sludge sample followed by a gas chromatographic measurement . By plotting the GC signal of water vapor vs. the headspace extraction number three different trend lines from the profile can be observed . From which two transition points can be determined and thus the stages for the free water capillary water and adsorption water release can be divided . Based on the sum of GC peak areas ate each stage the content of these water types in the sludge can be calculated through a method calibration . The results showed that the MHE GC method has a better measurement repeatability and sensitivity than the thermal drying method . There was also a good agreement between the MHE GC and the reference method on the free water and capillary water analysis . Moreover the results on the adsorption water and bound water testing by the present method is more justifiable than the reference method .
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Determining different types of water content and its distribution in sludge. It is based on a multiple headspace extraction gas chromatography MHE GC . The present MHE GC has a better performance than the reference method.
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S0021967320307263
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For choosing an optimal column for a particular separation by reversed phase liquid chromatography it is essential to quantitatively understand the effects of the chemical structure of hydrophobic bonded layer derived onto silica particles on the distribution equilibrium of a solute compound at the interface between the aqueous mobile phase and the packing material . However there is still a lack of understanding of the solute distribution equilibrium in RPLC separation due to the complexities of the chemistry at the interface between the mobile phase and the bonded layer . We successfully determined the distribution coefficients of various organic compounds concerning to their accumulation onto the water bonded layer interface and into the bonded layer from bulk water using surface bubble modulated liquid chromatography with octadecyl and phenyl hexyl bonded silica columns . The water phenyl hexyl bonded layer interface accumulates organic compounds much less than the water octadecyl bonded layer interface due to its lower interfacial tension and this result suggests that phenyl hexyl group orient their benzene ring facing toward water . On the other hand aromatic moiety of phenyl hexyl group enhances partitioning of the organic compounds into the bonded layer . Experimental findings in the present work demonstrated that the water bonded layer interface and the bonded layer itself have independent contributions to the solute distribution and the water phenyl hexyl bonded layer interface shows quite different solute retention selectivity from the water octadecyl bonded layer interface .
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The effect of aromatic moiety in the bonded layer on RPLC retention was clarified. Aromatic moiety reduces the solute retention at the water bonded layer interface. Thermodynamic analysis was made on the retention at water bonded layer interface. SBMLC is a powerful tool to investigate molecular distribution in RPLC systems.
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S0021967320307287
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Comprehensive two dimensional liquid chromatography offers increased peak capacity resolution and selectivity compared to one dimensional liquid chromatography . It is commonly accepted that the technique produces the best results when the separation mechanisms in the two dimensions are completely orthogonal which necessitates the use of gradient elution for each second dimension fraction . Recently the use of similar separation mechanisms in both dimensions has been gaining popularity but full or shifted gradients are still used for each second dimension fraction . Herein we argue that when the separation mechanisms are correlated in the two dimensions the best results can be obtained with the use of parallel gradients in the second dimension which makes the technique nearly as user friendly as comprehensive two dimensional gas chromatography . This has been illustrated through the separation of a mixture of 39 pharmaceutical compounds using reversed phase in both dimensions . Different selectivity in the second dimension was obtained through the use of different stationary phase chemistries and or mobile phase organic modifiers . The best coverage of the separation space was obtained when parallel gradients were applied in both dimensions and the same was true for practical peak capacity .
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LCLC separations can be performed using similar separation mechanisms in both dimensions. Different types of gradients were compared using emulated and real on line systems. Parallel gradients provide the best results when the separation mechanisms are correlated.
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S0021967320307378
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In this work high performance thin layer chromatography coupled with multivariate image analysis is proposed as a fast and reliable tool for authentication and adulteration detection of Iranian saffron samples based on their HPTLC fingerprints . At first the secondary metabolites of saffron were extracted using ultrasonic assisted solvent extraction which was optimized using central composite design . Next the RGB coordinates of HPTLC images were used for estimation of saffron origin based on principal component analysis . The PCA scores plot showed that saffron samples were clustered into two clear cut groups which was 92 matched with the geographical origins of the samples . In the next step common plant derived adulterants of saffron including safflower saffron style calendula and rubia were investigated with MIA analysis of HPTLC images using partial least squares discriminant analysis at 535 levels . The PLS DA results showed proper classification of saffron and adulterants with sensitivity 99.14 specificity 96.94 error rate 1.96 and accuracy 98.04 . Also the effect of HPTLC injection volume on the performance of the proposed strategy was evaluated . The ability of the proposed method was then investigated by analyzing two additional sample sets including mixed samples of four plant derived adulterants and adulterated commercial samples . Sensitivity and specificity of this model were 100 which confirmed its validity .
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Integration of HPTLC and MIA as a reliable method for saffron authentication. Optimization of USAE extraction factors by multivariate optimization. Exploration of saffron authentication by PCA. Development of different PLS DA models for detection of common saffron adulterations. Proper PLS DA results for reliable discrimination between authentic and adulterated saffron.
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S002196732030738X
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Despite the extensive use of electrospray ionization for the quantification of neuropeptides by liquid chromatography tandem mass spectrometry poor ionization and transmission efficiency are described for this ionization interface . A new atmospheric pressure ionization source named UniSpray was recently developed and commercialized . In this study the LC MS performance of this new ionization interface is evaluated and compared with ESI for the quantification of seven neuropeptides . Besides comparison of signal intensities and charge state distributions also signal to noise ratios and accuracy and precision were assessed . Additionally matrix effects of human precipitated plasma and rat microdialysate were evaluated as well as the effect of three supercharging agents on the ionization of the seven neuropeptides . UniSpray ionization resulted in signal intensities four to eight times higher at the optimal capillary impactor voltage for all seven neuropeptides . S N values at the other hand only increased by not more than a twofold when the UniSpray source was used . Moreover UniSpray ionization resulted in a shift towards lower charge states for some neuropeptides . Evaluation of the matrix effects by a post column infusion set up resulted in different infusion profiles between ESI and UniSpray . The charge state distributions of the neuropeptides obtained with UniSpray are highly comparable with ESI . Finally the effect of the supercharging agents on the ionization of the neuropeptides tends to be peptide dependent with both ionization sources .
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UniSpray results in four to eight times higher signal intensities. By use of UniSpray S N values only improved by less than a factor of 2. A small shift towards lower charge states is observed for UniSpray. When matrix effects were evaluated infusion profiles differed between both sources. Supercharging agents affect the peptides differently for both sources.
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S0021967320307391
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Cross reactivity is an important feature of molecularly imprinted polymers and is central to successful use of a pseudo template in molecular imprinting . The adsorption and cross reactivity of a molecularly imprinted polymer designed for recognition of phenols from water was assessed using four different isotherm models Freundlich LangmuirFreundlich and Brunauer Emmett and Teller . The L FI model succeeded in explaining the cross reactivity behavior through the total number of binding sites the affinity constants and heterogeneity indices of the small phenols 2 methylphenol 3 methylphenol 2 chlorophenol 2 4 dimethylphenol 2 4 dichlorophenol 4 chloro 3 methylphenol with evidence that the phenols compete for binding sites based on their hydrophobicity as well as and dipole dipole intermolecular forces . The recognition of the large phenols pentachlorophenol 4 teroctylphenol 4 nonylphenol which have much higher binding affinities than the smaller phenolic compounds was explained with the BET isotherm model that predicts that multiple layers adsorb to the adsorbed monolayer . The adsorption behavior with MIPs is also shown to be superior to corresponding non imprinted polymers and applicability of MIPs for trace analysis is highlighted .
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Simultaneous adsorption of eleven phenolic compounds by a catechol imprinted polymer. Evaluation of cross reactivity of MIPs toward phenols using 4 adsorption isotherms. Recognition mechanisms for MIPs are explained using adsorption isotherms. Adsorption of hydrophobic phenolics in layers is explained using the BET isotherm.
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S0021967320307408
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Red wine is a complex matrix containing macromolecules such as condensed tannins and polysaccharides . Wine macromolecular components and their interactions have been reported to impact taste properties such as astringency but the colloidal systems formed in wine are not well known . A key prerequisite to characterize these systems is the ability to work under analytical conditions as close as possible to the colloid environment preserving the sample structure and limiting the denaturation of macromolecular complexes . A method of Asymmetric Flow Field Flow Fractionation coupled with UV detection multi angle light scattering and differential refractometer index has been developed to analyse macromolecules including tannins and polysaccharides and macromolecular complexes in red wine . This method separates objects according to their hydrodynamic radius and does not require calibration to determine molecular weight M
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An AF4 MALS UV dRI method was developed to analyze red wine macromolecules. A4F profiles were interpreted after injecting tannin and polysaccharide fractions. Major fractions were attributed to higher M. polyphenols and polysaccharides. The molecular weights of the objects present in the fractions were determined. AF4 MALS is promising to investigate the M. distribution of tannins and macromolecules in wine matrix.
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S002196732030741X
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Modeling the chromatographic separations of proteins at manufacturing scale is important since downstream processing costs are often dominant . At such scales the columns are highly overloaded heightening the challenge of predicting performance . In this work the separation of a monoclonal antibody monomer dimer mixture is conducted by gradient elution chromatography with ceramic hydroxyapatite columns Type I and Type II under overloaded conditions . Phosphate gradients are shown to be preferable over sodium chloride gradients since the latter result in undesirable pH transitions generated within the column itself . Using sodium phosphate gradients separation is obtained with both CHT types achieving approximately 90 recovery at 99 monomer purity starting with a mixture containing 30 dimer at total protein loads up to 30 mg mL . Because of its higher binding capacity even higher loadings can be obtained with CHT Type I without monomer breakthrough . A hybrid model is developed to describe the separation . The model based on an empirical description of two component competitive isotherms at low sodium phosphate concentration coupled with the stoichiometric displacement model at higher sodium phosphate concentrations is in good agreement with the experiments using the linear driving force approximation to describe adsorption desorption kinetics . The same LDF rate coefficient predicts the separation at loadings between 0.8 and 30 mg mL . The model developed in this work can be used as a general tool to optimize operating conditions understand what factors limit performance and compare different operating modes .
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Antibody monomer dimer separation achieved by gradient elution with hydroxyapatite. 99 antibody monomer purity and 90 recovery obtained starting with 30 dimer. Hybrid model predicts performance as a function of protein load and gradient slope. Optimized protein loads lead to high productivity.
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S0021967320307469
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Hypercrosslinked polymers have demonstrated effective adsorption capabilities because of their richporosityandhighspecific surface area . However the HCPs prepared with phenylboronic acid based compounds as monomers via Friedel Crafts alkylation reaction have not been reported yet . Herein four new HCPs with phenylboronic acid 1 4 benzenediboronic acid 4 hydroxyphenylboronic acid and 4 carboxyphenylboronic acid as the respective monomers were prepared for the first time . Their Brunner Emmet Teller surface areas were 909.1 m
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Four novel boronic acid based hypercrosslinked polymers were newly synthesized. The porous polymers were investigated as the SPE adsorbents for the first time. The PBA based HCP exhibited high adsorption ability for some chlorophenols. An effective SPE method was established to enrich chlorophenols from real samples.
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S0021967320307470
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An automated inline sample preparation method has been developed for pesticide residue analysis in spinach by LC MS MS. Chlorophyll pigments and other matrix constituents were removed from the sample extract using a UHPLC system equipped with an auxiliary pump 6 port high pressure switching valve and dual directional ILSP cartridge containing bonded silica . The new procedure was evaluated as an entirely separate workflow using a simple solid liquid extraction and as part of a cleanup strategy in conjunction with QuEChERS . Accuracy and precision experiments were conducted in spinach at two concentration levels
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An automated inline sample preparation LC MS MS workflow for pesticide residue analysis. Analysis of 63 pesticides from spinach. Comparison to QuEChERS approach shows more pigment removal with less pesticide loss. Simpler faster and more amenable to automation than QuEChERS. Validation experiments show good method linearity and recovery.
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S0021967320307482
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Organic gel has excellent characteristics including a large surface area adjustable pore channel size and good chemical stability and has attracted great attention in the field of materials . However the OG packed column is difficult to pack due to the weak mechanical strength and poor monodispersity . Herein 1 allyl 3 methyl imidazolium hexafluorophosphate co 1 dodecanethiol PF
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The adhesion of organic gel simplify the synthesis of stationary phase materials. It doesn t need any silane coupling agent so it reduces the waste of raw materials. The prepared stationary phase materials can separate in multiple separation modes. A new idea of using organic gel as liquid chromatography packing for separation.
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S0021967320307494
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Liquid chromatography tandem mass spectrometry has been a widely used technique for quantifying oligonucleotides in biological samples . However lack of simple and efficient sample cleanup approach remains a challenge . Our study aimed to evaluate the major factors during the sample pretreatment process for developing optimal sample preparation workflow for oligonucleotides . In this study we have employed a model formed with rat plasma containing a 16 mer oligonucleotide standard in order to comprehensively optimize the sample preparation procedures . These included liquid liquid extraction solid phase extraction protein precipitation and LLE combined with SPE . LLE with phenol dichloromethane was found to be the most efficient sample cleanup procedure with low cost and less toxicity . Followed by the extraction ethanol precipitation was determined to be the optimal drying conditions . Also mass spectrometric parameters were tuned to optimal conditions . It was found that the central composite design suite was proved to be highly practical for optimizing MS parameters . Finally the thoroughly optimized sample preparation workflow was fully validated . The developed assay provided a quantitative range of 0.251000nM with accuracy and precision were 7.45 and 12.20 respectively . Matrix effect and carryover were also evaluated and no significant effect was observed .
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Phenol dichloromethane 2 1 v v surpassed other conventional extraction methods. Ethanol precipitation 80C 5min was the optimal drying conditions. The developed workflow provided a quantitative range of 0.251000nM. MS parameters were optimized through the central composite design.
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S0021967320307500
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A heart cut multidimensional gas chromatographymass spectrometry method for separation and identification of triacylglycerols in extra virgin olive oil was developed . A GC configuration comprising a non polar first dimension
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A high temperature multidimensional GC method is established for triacylglycerol analysis. The first dimension low polarity column gives incomplete separation of TAG components. Narrow multidimensional heartcuts are taken over regions of first column peak overlap. A medium polarity second column allows adequate separation of selected TAG components. Mass spectrometry is used to provide tentative identification of the TAG.
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S0021967320307512
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For successful profiling of aroma carriers in food samples a highly efficient extraction method is mandatory . A two step stir bar sorptive extraction approach namely fractionated SBSE was developed to improve both the organoleptic and the chemical identification of aroma compounds in beverages . Fr SBSE consists of two multi SBSE procedures
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Fractionated stir bar sorptive extraction Fr SBSE was developed. The method consists of conventional SBSE and solvent assisted SA SBSE. Two fractions apolar medium polar fraction and polar fraction are provided. The identification capabilities of aroma compounds in beverages are improved. Useful fractionation of individual sample sensory building blocks is possible.
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S0021967320307536
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This research developed a new methodology using a gas chromatograph a pulsed discharge helium ionization detector and two mass spectrometric detectors . The detectors worked simultaneously using 8 columns and 7 valves . This new proposal for simultaneous analysis with a single injection and analysis time of 36 min allowed the quantification of 10 oxygenated compounds 3 permanent gases 3 sulphides and 4 thiols which are aggressive inhibitors of the Ziegler Natta catalytic systems . The RSD for repeatability of the peak area of the 20 compounds analyzed and the retention time were less than 0.59 and 0.23 respectively . The RSD for intermediate precision for the peak area was less than 0.85 and for the retention time less than 0.35 . 95 of the inhibitors analyzed showed relative errors inter and intra day less than 3 . The inhibitors detected and quantified were formic acid acetic acid acetone methanol isopropyl alcohol ethanol 1 propanol 1 butanol 2 butanol tert butanol CO
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7 alcohols 2 acids CO CO. O. 1 ketone 3 sulfurs 4 thiols were identified and quantified. The 20 inhibitors decreased PP productivity between 5 and 20 . An MLR model with r. 0.9092 predicts the effect of 20 inhibitors on the ZN catalyst. MLR complies with residuals auto correlation multi co linearity and normality.
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S0021967320307548
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In this study the thermodynamics of binding of two industrial mAbs to multimodal cation exchange systems was investigated over a range of buffer and salt conditions via a van t Hoff analysis of retention data . Isocratic chromatography was first employed over a range of temperature and salt conditions on three multimodal resins and the retention data were analyzed in both the low and high salt regimes . While mAb retention decreased with salt for all resins at low salts retention increased at high salts for two of the resins suggesting a shift from electrostatic to more hydrophobic driven interactions . The retention data at various temperatures were then employed to generate non linear van t Hoff plots which were fit to the quadratic form of the van t Hoff equation . At low salts retention of both mAbs decreased with increasing temperature and the van t Hoff plots were concave downward on Capto MMC and Nuvia cPrime while being concave upward on Capto MMC ImpRes . Different trends were observed on some of the resins with respect to both the concavity of the van t Hoff plots as well as the impact of temperature on the favorable enthalpies in the low salt regime . Interestingly while increasingly favorable enthalpy with temperature was observed with Capto MMC and Nuvia cPrime at low salt favorable enthalpy decreased with temperature for Capto MMC ImpRes . At high salts binding of both mAbs on the two Capto resins were consistently entropically driven consistent with desolvation . While the negative heat capacity data at low salts indicated that desolvation of polar charged groups were important in Capto MMC and Nuvia cPrime the positive data suggested that desolvation of non polar groups were more important with Capto MMC ImpRes . Finally the data at high salts indicated that desolvation of non polar groups was the major driver for binding of both mAbs to the Capto resins under these conditions .
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Evaluated mAb retention on MM resins at various salt and temperature conditions. Data accurately represented by non linear van t Hoff plots at all the conditions. Enthalpic contributions were dominant at low salt concentrations on all resins. The binding of mAbs was entropically driven at higher salts on some of the resins. The heat capacity change upon adsorption was dependent on the salt concentration.
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S002196732030755X
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Separation of antipsychotic drugs from whole blood and urine is of great importance for clinic and forensic laboratories . In this work chlorprothixene haloperidol and risperidone representing the first and second generations of antipsychotic drugs were studied . Among them chlorprothixene and risperidone were investigated for the first time by electromembrane extraction . After the screening 2 nitrophenyl octyl ether was used as the supported liquid membrane . The EME performance for spiked water whole blood and urine was tested and optimized individually . Using NPOE and 60 V efficient EME was achieved from urine and whole blood with trifluoroacetic acid as the acceptor solution . The equilibrium time required for EME was dependent on the sample matrices . The steady state of EME was reached in 30 min and 20 min for whole blood and urine respectively . At steady state the EME recoveries of the targets from different sample matrices were satisfactory and were in the range of 74 100 . The proposed EME approach combined with liquid chromatography tandem mass spectrometry was evaluated using whole blood and urine . The obtained linearity was 1 200 ng mL
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The antipsychotic drugs of CPX and RIS were extracted by EME for the first time. Efficient EME of CPX HAL and RIS from whole blood and urine samples were achieved. The proposed EME combined with LC MS MS was validated using biological samples. EME LC MS MS was successfully applied to determine CPX HAL and RIS in rats.
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S0021967320307561
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A single step copolymerization strategy was developed for the preparation of carbohydrate functionalized monoliths using click reaction . Firstly novel carbohydrate functionalized methacrylate monomers were synthesized through Cu catalyzed 1 3 dipolar cycloaddition of terminal alkyne with azide of carbohydrate derivatives . The corresponding carbohydrate functionalized monolithic columns were then prepared through a single step
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A novel single step strategy was developed for carbohydrate monolithic column. Glucose and maltose functionalized monoliths were prepared and characterized. The optimized monoliths showed great potential for separation and enrichment.
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S0021967320307573
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Columns of different structures have different potential kinetic performance the trade off between separation time and pressure . However the full potential of a structure can not always be realized in practically existing columns . Each combination of column efficiency time and pressure requires certain cross sectional dimensions of the column flow through channels . However there are limits to the narrowest flow through channels that can be manufactured with current technology . As a result columns of some structures can not be optimized for providing the required efficiency in the shortest time . Additionally the full potential of its structure can be realized only if a column can operate at the highest pressure available from liquid chromatography equipment has sufficient loadability and satisfies other practical requirements .
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Structural quality factor quantifies potential column performance. To perform at its full potential dimensions of column structure should be sufficiently small. Several differently structured columns compared. Required dimensions of internal structure estimated.
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S0021967320307585
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Polymer grafting to porous materials is an effective way to create protein ion exchangers of high capacity and uptake rate because the 3D architecture of the polymeric ion exchange groups provides high binding space and facilitated transport of the bound protein . Herein a new anion exchanger was fabricated by grafting trimethyl ammonium chloride onto Sepharose FF gel for protein adsorption and chromatography . The ion exchanger denoted as FF pAPTAC presented high capacity but limited uptake rate in bovine serum albumin adsorption due to the high charge density of the cationic polymer chains . To solve the problem we proposed to copolymerize APTAC with an electroneutral monomer acrylamide onto Sepharose FF to modulate the charge density of the grafted polymer chains . By decreasing the feeding molar ratio of APTAC to AM the ionic capacity of the copolymerized resins FF pn decreased but the chain length could be remained almost unchanged due to the similar reactivity ratios of the two monomers . With decreasing IC the static adsorption capacity
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Fabrication of ion exchangers by copolymerizing cationic and electroneutral monomers. Introducing electroneutral monomer reduces chain charge density. Uptake rate enhanced 2.56.5 folds by the charge density reduction on chains. Dynamic binding capacity reached 147mg mL in the copolymer grated resins.
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S0021967320307603
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Per and polyfluoroalkyl substances have been determined in waters intended for human consumption causing concern due to their potential toxic effects in humans and the environment . Drinking water is acknowledged to be one of the major routes of exposure to PFASs which has led to the implementation of regulatory guidelines for PFASs in drinking water . In this study a fast simple sensitive and cost effective method is developed for the determination of 18 PFASs in river and drinking water . The proposed method consists of directly injecting 900 L of sample into a liquid chromatograph coupled to a triple quadrupole mass analyser which involves minimal sample treatment as the sample only needs to be filtered . The method was validated in influent and effluent water from a drinking water treatment plant . Strong matrix effects were found for some of the target PFASs and matrix matched calibration curves were performed to enable accurate and precise quantification
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The method developed is based on direct injection of 900 L. Increasing the injection volume from 500 L to 900 L did not increase matrix effects. Sub to low ngL. MQLs were achieved without the need of pre treatment of the sample. Short chain PFASs are not removed from the drinking water treatment plant. PFBA PFPeA PFHxS PFOS PFOA and PFHxA were the most abundant compounds.
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S0021967320307615
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In this work an inexpensive fast and selective ionic liquid modified graphene oxide was synthesized and electrochemically deposited on the inner surface of a stainless steel tube . Then it was applied for circulated headspace in tube solid phase microextraction of naphthalene from honey samples . Next the coated tube was replaced with the sample loop of a six port injection valve for on line desorption and further HPLC UV analysis of naphthalene . The sorbent was characterized by scanning electron microscopy transmission electron microscopy Fourier transform infrared spectroscopy and energy dispersive X ray spectroscopy . Different parameters affecting the procedure efficiency including extraction temperature extraction time salt concentration and sample volume were optimized by central composite design and response surface methodology . Under the optimum conditions the calibration curve was linear within the range of 0.3 200 ng mL
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1 methylimidazole modified grapheme oxide GO IL was synthesized as the sorbent. GO IL was electrodeposited on the inner surface of a stainless steel tube. The coated tube was applied in a circulated headspace in tube SPME procedure. Desorption and liquid chromatography analysis of the extracts was performed on line. The method was applied for determination of naphthalene in honey samples.
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S0021967320307706
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In the chromatographic separation process of oligonucleotides mechanistic understanding of their binding and diffusion processes is of significant importance to determine operating conditions in a fast and robust way . In this work we determined the number of binding sites and the diffusivities of ONs in a polymer grafted anion exchange chromatography through linear gradient experiments being carried out at selected four to five gradient slopes . Synthetic poly s with length ranging from 3 to 90 mer were employed as a model of an antisense oligonucleotide with typical lengths of 10 30 bases . Comparison of the retention was also conducted between the grafted anion exchanger with a conventional ligand and an anion monolith disk . For the ONs up to 50 bases the number of binding sites determined can be correlated with the length of ONs and the grafted resin showed a better diffusion and narrower peak width compared to the nongrafted one . The retention behavior became similar for porous media when the longer ONs were applied . The results obtained suggest that antisense ONs can be separated with grafted ligands without sacrificing mass transfer properties .
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The number of binding sites and oligonucleotides length have a linear correlation. When using grafted resins intraparticle diffusion depends on salt concentration. Intraparticle diffusion affects HETP less in grafted beads for long oligonucleotides. Grafted resins have less intraparticle diffusion limitations among porous resins.
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S0021967320307718
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Profiling the chemical components of complicated herbal extracts using traditional analytical methods is time consuming and laborious . In this study an integrated data filtering and identification strategy was developed to efficiently identify the chemical constituents in
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An integrated data filtering and identification strategy is proposed. Background subtraction mass defect filtering MDF and diagnostic ion filtering. The resulting simplified data could facilitate the identification of the compounds. 96 compounds including nine unknowns were identified from. A powerful material basis for quality control of. was obtained.
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S002196732030772X
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Allylglycine a conventional amino acid derivative possesses typical zwitterionic and hydrophilic functionalities deriving from the carboxyl and amino groups in its structure . A novel monolithic column poly allylglycine
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Glycine modified monoliths with polar amino and carboxyl groups are good for HILIC. Allylglycine is firstly used for the preparation of hydrophilic monolithic column. The column offers prominent hydrophilic selectivity even at 50 organic phase. Highest separation efficiency up to 1.4110. N m. for theophylline.
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S0021967320307731
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A green air assisted dispersive liquid liquid microextraction based on floating organic droplet solidification was introduced for the enrichment of five endocrine disrupting compounds from water using a ternary deep eutectic solvent as an extracting solvent prior to their determination by HPLC PDA . The eutectic solvents were synthesized by combining various fatty acids which can concurrently act as both hydrogen bond acceptors and hydrogen bond donors . Adding a third component to classical two component eutectic solvents allows to purposefully control density melting point and viscosity of the synthesized solvents . Ternary and binary eutectic solvents with C9 acid provided excellent extraction efficiency in comparison with other eutectic solvents with C8 acid while ternary solvents provided superior extraction efficiency to binary ones . Different variables that could influence the microextraction efficiency were optimized applying central composite face centered design . At the optimum conditions the method had low detection limits ranging from 0.962.30g L with a preconcentration up to 134 folds . The method showed good linearity from the linear regression with an excellent correlation coefficient
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Ternary eutectic solvents were utilized for DLLME SFOD of endocrine disruptors. The method was optimized by central composite face centered design. A preconcentration up to 134 folds was achieved. Low detection limits from 0.96 to 2.30g L with excellent precision were achieved. The method greenness was evaluated by Raynie pictogram eco scale and GAPI tools.
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S0021967320307743
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Efficient and economical separation and enrichment of high content class compounds from complex natural plants are of great importance . This study describes a novel continuous chromatography system with multi zone and multi column dynamic tandem techniques for the efficient and economical separation and enrichment of high content class compounds from natural products . The CCS was split into eight zones via a multi channel logic control valve to continuously and automatically separate and enrich class compounds from complex natural plants . CCS separation conditions were optimized by static and dynamic adsorption and desorption experiments . With the CCS system 120.82 kg of
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A novel CCS with multi zone and multi column dynamic tandem isolation was developed. 120.82 kg of. saponins with high content was successfully isolated by the CCS. The separation time of 1.0 t of. was only 33.3 hours. The usage of the mobile phase was only 1 3 1 2 of that of traditional macroporous resin.
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S0021967320307755
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To facilitate faster selectivity evaluation of wall coated open tubular columns using the solvation parameter model a reduced set of calibration compounds is identified and validated for the temperature ranges 60 140 C and 160 260 C. The Kennard Stone uniform mapping algorithm is used to identify the calibration compounds from a larger database of compounds with known retention properties previously adopted for column selectivity evaluation . Thirty five compounds for each temperature range are required to minimize the standard deviation of the system constants used for selectivity evaluation and to minimize differences between system constants determined by conventional calibration and the reduced calibration compounds . The models for the reduced calibration compounds on ten siloxane based and poly stationary phases have a coefficient of determination of 0.984 to 0.998 and standard error of the estimate of 0.012 to 0.30 . The predictive capability of models is evaluated for the reduced sets of calibration compounds using external test sets with ranking of the calibration models by changes in the average error average absolute error and root mean square error of prediction for the test sets . For the selected thirty five reduced calibration compounds the range for the average absolute error was 0.014 to 0.033 and 0.016 to 0.040 for the root mean square error of prediction for the independent test sets .
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Identification of calibration compounds for selectivity evaluation. Selectivity evaluated over the temperature range 60 260 C. Reduced calibration models as accurate as traditional models with a SE of 0.012 to 0.030. Predictive capability of the calibration models had a RMSEP of 0.016 to 0.040. Faster construction of system maps are a typical application.
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S0021967320307767
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Metabolic stability tests are one of the fundamental steps at the preclinical stages of new drug development . Microsomes used as a typical enzymatic model of liver biotransformation can be a challenging matrix for analytical scientists due to a high concentration of cellular proteins and membrane lipids . In the work we propose a new procedure integrating biotransformation reaction with SPME like protocol for sample clean up . It is beneficial to increase the overall quality of results in contrary to the typical protein precipitation approach . A set of ten arylpiperazine analogs six of which are considered promising drug candidates were used as a probe to assess the goodness of the newly proposed approach . In order to promote an efficient extraction protocol a new miniaturized shape of a sorbent suitable to perform the extraction in 100 L of the sample has been designed . Termination of the biotransformation process by protein denaturation with hot water was additionally evaluated . A quantitative structure property relationship study using Orthogonal Partial Least Squares technique to reveal insights to the sorption mechanism was also performed . The obtained results showed the new 3D printed sorbent can be an attractive basis for the new sample preparation approach for metabolic stability studies and an alternative for commercially available protocols based on solid phase microextraction or solid phase extraction principles .
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The 3D printed sorbent is coupled to the metabolic stability test of drug candidates. Customizable sorbent enhances the performance of LC MS analysis at low cost of sample clean up. The additional extraction step improves the precision of drug candidates t. determination.
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S0021967320307779
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The first quantitative multiclass approach enabling the accurate quantification of 1200 biotoxins pesticides and veterinary drugs in complex feed using liquid chromatography tandem mass spectrometry has been developed . Optimization of HPLC UHPLC and MS MS conditions were carried out in order to allow the combination of five major substance classes and the high number of target analytes with different physico chemical properties . Cycle times and retention windows were carefully optimized and ensured appropriate dwell times reducing the overall measurement error . Validation was carried out in two compound feed matrices according to the EU SANTE validation guideline . Apparent recoveries matching the acceptable range of 60 140 accounted 60 and 79 for all analytes in cattle and chicken feed respectively . High extraction efficiencies were obtained for all analyte matrix combinations and revealed matrix effects as the main source for deviation of the targeted performance criteria . Concerning the methods repeatability 99 of all analytes in chicken and 96 in cattle feed complied with the acceptable RSD 20 criterion . Limits of quantification were between 1 10 g kg for the vast majority of compounds . Finally the methods applicability was tested in 130 real compound feed samples and provides first insights into co exposure of agro contaminants in animal feed .
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An LCMS MS method for biotoxins pesticides and veterinary drugs was developed. Full validation of 1219 multi class contaminants in two complex feed matrices. Extraction meets 70120 criterion for 91 95 of analytes in cattle and chicken feed. Limit of quantification of 1000 analytes below 10 g kg in both matrices. Relative matrix effects 15 for 79 91 of analytes in cattle and chicken feed.
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S0021967320307780
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Colorectal cancer is one of the most serious complications of ulcerative colitis . Altered gut microbiota is implicated in the development of CRC and metabolic perturbations are often associated with changes in the gut microbiome composition . Given the links between gut microbiome and the metabolic profiles in the body an approach involving ultra high performance liquid chromatography combined with electrospray ionization quadrupole time of flight tandem mass spectrometry metabolomics and 16S rDNA sequencing technology was applied to trace the development UC into CRC in rats . The study identified 11 differential metabolites related to both UC and CRC which mainly referred to the linoleic acid metabolism . Among these linoleic acid and 12hydroxy8 10 octadecadienoic acid could serve as key biomarkers for the development of UC into CRC . Besides a significant change was observed in the microflora structure during the development from UC to CRC this mainly involved a gradual increase in
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Developed an original nontarget metabolomics UHPLC Q TOF MS MS method. Identified and confirmed characteristic metabolites and intestinal microbiota. Excavated a strong correlation between typical microflora and metabolites. Results could provide targets for the prevention and treatment of UC to CRC.
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S0021967320307792
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A modified method for the Craig scheme solution applied for a chromatographic column has been proposed and the corresponding implicit code is presented . The new approach improves the mass conservation problem frequently reported during the numerical solution of the Equilibrium Dispersive model with Craig scheme . The modified code has been successfully verified in gradient chromatography conditions by comparison with the reliable solutions of the Equilibrium Dispersive model by the Orthogonal Collocation on Finite Elements . The errors obtained with the modified Craig method are less than about 1 in the case of retention times and less than about 11 in the case of apparent number of theoretical plates comparing to the OCFE solutions .
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Mass conservation problem using original Craig scheme solution. Modified method for the Craig scheme solution was proposed. Modified code successfully verified in gradient chromatography conditions.
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S0021967320307809
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Immobilized metal affinity chromatography is a technique primarily used in research and development laboratories to purify proteins containing engineered histidine tags . Although this type of chromatography is commonly used it can be problematic as differing combinations of resins and metal chelators can result in highly variable chromatographic performance and product quality results . To generate a robust IMAC purification process the binding differences of resin and metal chelator combinations were studied by generating breakthrough curves with a poly histidine tagged bispecific protein . The optimal binding combination was statistically analyzed to determine the impact of chromatographic parameters on the operation . Additionally equilibrium uptake isotherms were created to further elucidate the impact of chromatographic parameters on the binding of protein . It was found that for protein expressed in CHO cells Millipore Sigma s Fractogel EMD Chelate charged with Zn
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IMAC resin and chelator combinations screened for a histidine tagged novel molecule. Fractogel EMD Chelate M charged with zinc identified as highest binder in screen. Statistical study identified key factors resin lot capacity and histidine tag length. Equilibrium isotherms outlined the binding of poly histidine tagged proteins. Robust IMAC operation successfully scaled up.
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S0021967320307810
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The development of a new lower cost method for trace explosives recovery from complex samples is presented using miniaturised click together and leak free 3D printed solid phase extraction blocks . For the first time a large selection of ten commercially available 3D printing materials were comprehensively evaluated for practical flexible and multiplexed SPE using stereolithography PolyJet and fused deposition modelling technologies . Miniaturised single piece connectable and leak free block housings inspired by Lego were 3D printed in a methacrylate based resin which was found to be most stable under different aqueous organic solvent and pH conditions using a cost effective benchtop SLA printer . Using a tapered SPE bed format frit free packing of multiple different commercially available sorbent particles was also possible . Coupled SPE blocks were then shown to offer efficient analyte enrichment and a potentially new approach to improve the stability of recovered analytes in the field when stored on the sorbent rather than in wet swabs . Performance was measured using liquid chromatography high resolution mass spectrometry and was better or similar to commercially available coupled SPE cartridges with respect to recovery precision matrix effects linearity and range for a selection of 13 peroxides nitramines nitrate esters and nitroaromatics . Mean recoveries from dried blood oil residue and soil matrices were 79 24 71 16 and 76 24 respectively . Excellent detection limits between 60 fg for 3 5 dinitroaniline to 154 pg for nitroglycerin were also achieved across all matrices . To our knowledge this represents the first application of 3D printing to SPE of so many organic compounds in complex samples . Its introduction into this forensic method offered a low cost on demand solution for selective extraction of explosives enhanced flexibility for multiplexing design alteration and potential application at scene .
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Low cost fritless and leak free 3D printed SPE blocks successfully developed. A methacrylate based housing was compatible with most SPE solvents acids and bases. Mean recoveries from blood oil and soil were 70 for several trace explosives. New SPE blocks enabled detection limits of 60 fg 154 pg in matrix with LC HRMS. Application to contaminated soil samples revealed occurrence of 11 explosives.
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S0021967320307834
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In the present document we report the development of an analytical method consisting of a sequential direct immersion headspace solid phase microextraction followed by gas phase chromatography and tandem mass spectrometry for simultaneous analysis of 4 chlorobenzyl alcohol 2 6 dichlorobenzyl alcohol 4 methoxybenzyl alcohol 3 4 dimethoxybenzyl alcohol pyridine and 2 3 dimethylpyrazine in oilfield production waters . These compounds are under evaluation for use as phase partitioning tracers in oil reservoirs . To the best of our knowledge this is the first time SPME has been applied to the analysis of these compounds in production waters or any other type of matrix where the compounds targeted are the base for a technical application . Relevant extraction parameters such as the adsorbent phase of the fiber direct immersion or headspace addition of salt temperature and time of extraction were investigated . The final optimal operation conditions consist on extracting 5 mL of sample at pH 9.0 with 1.8 g of NaCl with constant stirring during 5 minutes of DI SPME followed by 15 minutes of HS SPME at 70 C using a DVB CAR PDMS fiber . The limits of quantification linearity precision and accuracy of the method were evaluated . Analyses of the tracer compounds and recovery studies were also performed on production waters from 8 different oilfields of the Norwegian continental shelf . LOQs between 0.080 and 0.35 g L
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SPME was applied to oilfield production waters. A method consisting of DI HS SPME GC MS MS was developed. 6 compounds of 3 families of chemicals were targeted. LOQs on the ng L. range were achieved.
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S0021967320307858
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A two dimensional system composed of supercritical fluid chromatography and reverse phase liquid chromatography coupled a tandem mass spectrometry was developed for the quantitative analysis of vitamin D in daily oily supplements . Two six port switching valves are configured allowing four different valve positions . When the valve positions were fixed at Position A this system worked at SFC MS mode . When the valve positions switched between Position B and C this system worked at a SFC LC MS switching mode . Vitamin D3 in two kinds of oily drops Baby Ddrops and Vitamin AD drops was determined at both SFC MS and SFC LC MS switching modes by using the same system . The linearity repeatability and recovery were investigated using the internal and external standard methods for the two modes . The results obtained from the internal standard method are better than those of the external standard method at either mode . The coefficient of determination r
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A two dimensional column switching system involving SFC and RPLC MS is developed. The system works at SFC MS or SFC LC MS mode through switching two six port valves. Vitamin D in oily supplements can be determined simply and fast using this system. SFC LC MS can get more accurate result with better precision even if using ES method.
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S0021967320307871
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This study reports a simple and convenient analytical method for the simultaneous determination of biodiesel and vegetable oils or used cooking oils in petrodiesel and green diesel . The approach is based on normal phase high performance liquid chromatography with refractive index detection . It employed silica stationary phase n hexane mobile phase with isopropanol modifier to achieve optimum separation between hydrocarbons fatty acid methyl esters and triglycerides . In addition to determining vegetable oils or used cooking oils as adulterants in diesel this method is also proposed as a better alternative to the standard method ASTM
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Simultaneous determination of biodiesel and vegetable oils used cooking oils in petrodiesel and green diesel. Simple efficient cost effective and robust normal phase HPLC method with only 7min runtime. The proposed method overcomes the limitations of standard methods ASTM. IP 39107 and BS EN 12 916 2019 in biodiesel determination. The method aims to verify diesel adulterants and support monitoring of diesel quality as per the indian regulatory specifications IS 1460 2017 .
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S0021967320307883
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Extracellular vesicles exist in biological fluids such as blood urine and cerebrospinal fluid and these have shown promise for use as biomarkers of cancers . Conventional methods for determination of EVs include direct detection via enzyme linked immunosorbent assay and detection of their membrane proteins via western blotting . These techniques however have individual shortcomings in terms of the need for large sample consumption processes that are time consuming and a lack of the capacity for quantification . In this study we developed a method to determine the EV membrane protein CD63 by coupling capillary electrophoresis immunoassay with laser induced fluorescence . In this process the EVs were isolated from a culture medium and were subsequently reacted with a fluorescently labeled anti CD63 antibody to form a CD63 complex localized on the surface of EVs . After removing the EVs containing the CD63 immune complex by centrifugation the supernatant containing the free fluorescent antibody was injected into a capillary to serve as a sample . A decrease in the peak area of the free fluorescent antibody became apparent when the amount of EVs was increased while that of the fluorescent antibody remained constant . The peak areas were decreased proportionally against the increased amounts of EVs . The concentration of the CD63 could then be estimated based on the slope of the linear relationship . This study is the first to quantify CD63 immobilized on EVs via CEIA LIF which is a novel method with the potential to determine membrane proteins localized on the surface of EVs .
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A sensitive capillary electrophoresis immunoassay for a membrane protein CD63 in extracellular vesicles was developed. A novel concept for an indirect capillary electrophoresis immunoassay is proven by the determination of CD63. CD63 immobilized on extracellular vesicles was quantified for the first time. This method requires low consumption of both reagents and samples.
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S0021967320307895
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In this work a cyclodextrin functional vinyl monomer was synthesized and the common moiety of five amanita toxins was used as the template for preparing molecularly imprinted polymers . Chemical calculation was used to evaluate and describe the binding interactions between the template and the functional monomer . The preparation conditions were optimized and the resultant MIPs were characterized and employed as solid phase extraction sorbents . The SPE conditions including the amount of sorbent extraction solution and eluting solution were also optimized for the enrichment of the five toxins . Using an ultra high performance liquid chromatography tandem mass spectrometry detection limits ranging from 0.340.42g L 0.160.33g L and 0.0350.056g kg were achieved for the five toxins in serum urine and liver samples respectively . The proposed method was further applied to the determination of the amanita toxins in suspected samples and showed great potential in the diagnosis of mushroom poisoning .
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Determination of five amanita toxins in biological samples using MIPs coupled with UPLC MS MS. A cyclodextrin functional vinyl monomer was synthesized and the common moiety of toxins was used as the template for preparing MIPs. A higher level of analytical performance was achieved as compared to previous works. The method was applied to the determination of the amanita toxins in suspected samples and showed great potential in the diagnosis of mushroom poisoning.
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S0021967320307901
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In the current study a robust dispersive solid phase extraction strategy using reduced graphene oxide zinc oxide nanocomposite as the sorbent was proposed for separation purification and enrichment of 12 mycotoxins in
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rGO ZnO composites were synthesized characterized and used as dSPE sorbents. dSPE was proposed for purification and enrichment of 12 mycotoxins in Huanglian. Quantification of multiple mycotoxins by UHPLC MS MS detection coupled with dSPE. Desirable linearity sensitivity recovery and precision were achieved.
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S0021967320307986
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In this study a dispersive solid phase extraction method was combined with solidification of floating organic dropliquidliquid microextraction based on in situ synthesis of deep eutectic solvent . It was used for the extraction of some phytosterols from edible oil samples . The extracted analytes were quantified by gas chromatographymass spectrometry . In this procedure the sample lipids are saponified with sodium hydroxide and then the analytes are adsorbed onto an octadecylsilane sorbent . After that the analytes are desorbed from the sorbent with ethanol as an elution solvent and the eluant is diluted with deionized water to obtain a homogenous solution . Then a few amounts of choline chloride and
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DSPE combined with deep eutectic solventbased SFO DLLME has been developed. GCMS system was used for quantification phytosterols. The method was applied to determine phytosterols in edible oils. Simplicity low cost less toxicity and effective sample preparation are advantages of the method.
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S0021967320308001
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The behavior of a novel type of SFC injector the feed injector was investigated . In SFC the sample compounds are usually diluted in a solvent which has a higher elution strength than the mobile phase which leads to solvent mismatch upon injection and evidently band broadening . The feed injector differs from standard injectors as the sample contained in the sample needle or loop is not switched in line with the mobile phase flow but directly injected added to the mobile phase flow
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The novel SFC feed injector that adds the sample to the mobile phase stream was investigated. Optimal feed speed is a trade off between injection solvent mismatch and sample dilution. The overfeed volumes increases band broadening and is best replaced by an apolar solvent. Partial sample injection can further decrease injection band broadening.
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S0021967320308013
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A self separating analyte compatible and efficient clean up method for QuEChERS extracts was designed and developed based on dispersive solid phase extraction using a branched polyethylenimine and nanoscale CaSO
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A functionalized carbon nanotubes nanohybrids was first synthesized and used as r DSPE sorbent. A self separating strategy was reported for the first time. The use of nanohybrids overcomes the limitations in low recoveries for planar pesticides using MWCNTs. The nanohybrids exhibits high clean up efficiency to remove matrix interferences. The method is time and labor saving cheap sensitive accurate and precise for multi residue analysis in vegetables and fruits.
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