Filename
stringlengths 17
17
| Abstract
stringlengths 76
3.38k
| Highlights
stringlengths 80
1.73k
|
|---|---|---|
S002196732030008X
|
A model based approach for scaling up chromatographic capture step was developed . The purification of human basic fibroblast growth factor protein 2 from an
|
Model based approach for scaling up chromatographic capture step was developed. Model system for the study was fibroblast growth factor protein from an. homogenate. Dynamic model was formulated which was used to scale up the operation. Effects of feed viscosity and competitive adsorption of impurities were accounted for.
|
S0021967320300091
|
A sensitive and selective method was developed and validated for the determination of 26 anticoccidial compounds in surface and groundwater samples at parts per quadrillion pgL
|
Highly polar and other anticoccidials can be separated on one analytical column. SPE allows for the efficient isolation of 26 anticoccidials from water. Validation has proven the method s applicability to surface and groundwaters. The method s detection capability ranges from ppq pgL. to ppt ngL. levels.
|
S0021967320300303
|
The behavior of isotactic syndiotactic and atactic polypropylene stereoisomers on porous graphitic carbon at different column temperatures is investigated with 1 decanol decalin and decane as the adsorption promoting solvents using gradient interaction chromatography . Column temperatures between 120180C are investigated for the three adsorption promoting solvents with 1 2 4 trichlorobenzene as the desorption promoting solvent . Owing to the different stereochemistry of the isomers their interaction with the atomic level flat surface of porous graphitic carbon is observed to be different when injected from the three different adsorption promoting solvents . Atactic and isotactic polypropylene are not separable when 1 decanol is used as the adsorption solvent but can be separated from syndiotactic PP at column temperatures of between 120 180C . The three stereoisomers have almost similar elution volumes when decalin is used as the adsorption promoting solvent between 120 170C . Decane allows for both adsorption and desorption of the stereoisomers at distinct peak elution volumes at the studied column temperatures of 120 160C . Furthermore it is shown that increasing the column temperature while maintaining other chromatographic conditions can either decrease or increase retention depending on the adsorption promoting solvent . More importantly retention is influenced by adsorption conditions which may affect macromolecular conformations upon injection onto the PGC stationary phase . This is the first study on PP stereoisomers highlighting this behaviour .
|
Retention of polypropylene stereoisomers on Hypercarb is dependent on tacticity adsorption promoting solvent and temperature. Column temperature affects retention either negatively of positively depending on adsorption promoting solvent. All polypropylene stereoisomers retained on porous graphitic carbon with decane as the adsorption promoting solvent.
|
S0021967320300340
|
Prostaglandins are vitally important unsaturated fatty acids involved in arachidonic acid metabolism participating in numerous pathophysiological processes especially in maintaining the homeostasis of uterus . Therefore quantitative analysis of PGs is of great importance for uncovering potential mechanisms of PGs related diseases . However methods for determining PGs in uterine samples have not been reported . In this study an ultra high performance liquid chromatography mass spectrometry method was established to quantify PGs in uterine samples using N N Dimethylethylenediamine and N N Diethylethylenediamine as derivatization reagents . The derivatization could be finished at 37C for 30min catalyzed by 1 N N N N Tetramethyl O uronium hexafluorophosphate . This is a mild condition suitable for most of biological samples . The DMED labeling of PGs could significantly enhance their response compared to those of underived ones . This method exhibited excellent linearity R
|
The derivation of PGs by DMED have high derivation efficiency under mild condition. PGs derivatized with DEED can be used as internal standards. The sensitivity of PGs were increased about 100 fold compared with underived ones. Prostaglandins in uterus of AUB rat model were successfully quantified.
|
S0021967320300352
|
The present contribution reports on the practical implementation and validation of a new experimental method to determine the radial dispersion D
|
Flow segmentation can be used to measure radial dispersion coefficient D. in practice. Mass flow meter feedback can be used to correct flow rate mismatches. Method validated by showing independence of relative central flow rate and tracer concentration. Measured D. values higher than in most engineering literature reports but still within cited range.
|
S0021967320300364
|
Affinity adsorbents have been the cornerstone in protein purification . The selective nature of the molecular recognition interactions established between an affinity ligands and its target provide the basis for efficient capture and isolation of proteins . The plethora of affinity adsorbents available in the market reflects the importance of affinity chromatography in the bioseparation industry . Ligand discovery relies on the implementation of rational design techniques which provides the foundation for the engineering of novel affinity ligands . The main goal for the design of affinity ligands is to discover or improve functionality such as increased stability or selectivity . However the methodologies must adapt to the current needs namely to the number and diversity of biologicals being developed and the availability of new tools for big data analysis and artificial intelligence . In this review we offer an overview on the development of affinity ligands for bioseparation including the evolution of rational design techniques dating back to the years of early discovery up to the current and future trends in the field .
|
Affinity absorbents are essential tools in protein isolation and purification. Rationally designed affinity ligands increase the purification performance for a specific target. Affinity ligands found by screening combinatorial libraries provide the basis for new adsorbents. Rational design of affinity ligands can be improved with the support from big data and artificial intelligence tools.
|
S0021967320300376
|
Eicosapentaenoic acid and docosahexaenoic acid are high nutritional components . Evidence for unique effects of them is increasing . Further understanding of their independent biological functions urgently needs more efficient separation techniques . Nowadays most of the commercially available fish oil products are the mixture of eicosapentaenoic acid ethyl ester and docosahexaenoic acid ethyl ester . It will be convenient to directly separate esterified EPA and DHA without saponification pretreatment . However it is of great challenge to separate EPAEE and DHAEE because of their extremely fat soluble nature and the equivalent chain length rule . In this research the suitability of green guanidinium ionic liquid in countercurrent chromatography solvent system for the separation of them was evaluated for the first time . Compared with imidazolium IL and phosphonium IL guanidinium IL based non aqueous biphasic system showed more outstanding separation performance . The separation mechanism was elucidated in depth through quantum mechanical calculations . It was found that guanidinium IL acted a crucial role in the CCC separation which resulted in difference of partition behavior of EPAEE and DHAEE via different hydrogen bonding affinity . EPAEE and DHAEE were successfully separated by solvent system
|
A novel biphasic system based on green guanidinium ionic liquid was developed. Successful separation was achieved with high loading capacity yield and purity. Performance of ionic liquid was interpreted with help of profile and surface. Preparative separation was efficient without resolution loss and time extension. A simple method was proposed for recovery of targets and recycling of ionic liquid.
|
S0021967320300388
|
Capillary electrophoresis tandem mass spectrometry is an interesting tool for proteomic analysis as the separation principle is orthogonal to liquid chromatography tandem mass spectrometry . The combination of both techniques can bring complementary information to enlarge proteome coverage .
|
Two sample preconcentration approaches were optimized to improve sensitivity. DPJ provided better results than t ITP in terms of peak width and peak height. Triple tube and EMASS interfaces for CEMS were compared. The number of identified peptides and proteins was compared using both interfaces.
|
S002196732030039X
|
Esters of fruit acids including acetic acid and mono and diacylglycerols also known as E472 emulsifiers are used in the food industry as food additives to adjust techno functional properties like viscosity emulsion stability and foaming stability in various products mainly dairy products . Based on the respective acids E472 emulsifiers are classified in several categories with acetic acid esters lactic acid esters citric acid esters and mono and diacetyl tartaric acid esters as the most prominent representatives . Besides fruit acid esters E472 emulsifiers mainly comprise MAG DAG triacylglycerols free fatty acids free fruit acids and free glycerol in different amounts . Here we present an innovative and sensitive method for the characterization of the composition of E472 emulsifiers by high performance thin layer chromatography with fluorescence detection . For HPTLCFLD technical emulsifiers were simply dissolved and analyzed on HPTLC silica gel plates after a two fold development and derivatization with primuline enabling the easy characterization and direct visual comparison of the emulsifier pattern through the fluorescent lipid components under UV366nm . Thus the HPTLCFLD fingerprint approach represents a simple tool for the comparison of different samples batches and categories of E472 . Coupling of HPTLC to mass spectrometry moreover enabled the identification of constituents of interest .
|
An easy characterization for E472 food emulsifiers was developed. HPTLC screening with sensitive fluorescence detection was performed. Visual detection of emulsifier patterns was assessed. Elegant comparison of samples and batches through fingerprints was introduced. HPTLCMS offered the identification of constituents of interest.
|
S0021967320300406
|
Large RNAs including messenger RNAs are promising candidates for development of new drug products and vaccines . Development of high resolution methods for direct analysis of large RNAs especially for purity in general and size or length in particular is critical to support new drug development and manufacture . However resolution based on size or length for large RNAs is limited even by capillary electrophoresis which is one of the most efficient separation methods for nucleic acids in general . This paper presents a capillary gel electrophoresis method for separating large RNA molecules by size or length under strongly denaturing non aqueous conditions . We believe that our work constitutes the first time that a gel suitable for CGE prepared with high molecular weight polymers and using only formamide as solvent has been successfully employed to analyze large RNAs on the basis of their size or length with high resolution . With an eye toward application for mRNAs in particular separation conditions in this work were optimized for RNAs approximately 2000 nucleotides in length . As compared to a standard CGE method using an aqueous gel resolution for commercially available RNA ladder components at 1500 and 2000nt is increased approximately 6 fold . The impacts of polymer type molecular weight of the polymer and polymer concentration on the separation were studied and optimized . Analysis of the results presented here also provides guidance for optimization of separation conditions for RNAs with different sizes as needed for particular applications in the future .
|
A highly efficient CGE method using non aqueous gel under denatured conditions was developed for separation of large RNA molecules. CGE conditions were optimized for analysis of mRNA with approximately 2000nt. The mechanism of the separation was investigated using logarithmic plot. The application of the CGE method was demonstrated using an mRNA drug substance.
|
S0021967320300418
|
For this work a novel air assisted liquid liquid microextraction based on solidification of floating deep eutectic solvent coupled with a high performance liquid chromatography method was developed for the detection of benzophenone and salicylate ultraviolet filters in water samples . Three types of fatty acid based hydrophobic deep eutectic solvents with low viscosity low density and melting point close to room temperature were prepared and employed as extraction solvents . This air assisted liquid liquid microextraction was carried out in a glass centrifuge tube . Subsequently the glass tube was introduced into ice water bath and held for 3min during which the upper DES phase was solidified . The water phase was easily extracted using a syringe equipped with a long needle and later the glass tube was removed from ice water bath . The solidified DES phase was immediately melted at room temperature and used for HPLC analysis . The response surface methodology was employed to optimize some influencing parameters such as the volume of the extraction solvent the pH value of sample solution the number of extraction cycles and the addition of salt . A quadratic model namely a central composite design was used to replace the conventional single factor analysis . It was found that under optimal conditions the limits of determination and quantification were 0.0450.54gL
|
Novel AA LLME based on solidification of floating DES method was developed. DESs with low viscosity density and melting point near room temperature were used. Central composite design was used for the method optimization. This method is simple low cost centrifugal free and environment friendly.
|
S0021967320300613
|
A new strategy for the preparation of mixed mode chromatographic stationary phases based on modified dialdehyde cellulose was proposed . Two novel mixed mode chromatographic stationary phases dicarboxyl cellulose modified silica DCC SiO
|
The preparation strategy of DAC based mixed mode stationary phases was proposed. The both columns were prepared by utilizing the easy functionalization of DAC. The HILIC IEC column and HILIC IEC chiral separation column were developed. The both columns had good chromatographic performance in each separation mode.
|
S0021967320300662
|
Abraham model correlations reported by Marlot and coworkers for the 1 octanol water 1 butanol water ethyl acetate water and heptane methanol biphasic partitioning systems are compared to previously published Abraham model correlations . The previously published correlations for the fore mentioned partitioning systems are based on more experimental data points and exhibit much better descriptive ability as evidenced by much smaller standard deviations standard errors and larger squared correlation coefficients .
|
Published Abraham model eqns. found for 4 biphasic systems studied by Marlot etal. Authors and published Abraham model log P equationss differ greatly. Authors Abraham model eqn. does not describe experimental octanol water data
|
S0021967320300674
|
p53 is a tumour suppressor gene that has been explored for cancer gene therapy as a possible alternative to the common treatments . The use of plasmid DNA to carry the therapeutic gene has been considered but it is requisite to preserve its supercoiled structure for eliciting a more effective gene expression and therapeutic action . The purification of the sc pDNA using amino acids based affinity chromatography has been successfully applied exploring different amino acids and supports . From these studies it stood out the selectivity of arginine for the recognition of sc pDNA . However some limitation on the binding capacity was found in the arginine agarose support and in the case of monoliths some fouling and clogging can limit sequential runs . By using macroporous support modified with arginine it was expected to take advantage of the selectivity of the ligand combined with the flow properties and binding capacity offered by the support . The arginine modified macroporous support was characterized by SEM EDX and FTIR also to verify the correct immobilization of arginine and then used for pDNA purification . The support showed to be effective on the sc p53 pDNA isolation and the robustness was also achieved by accomplishing the purification of plasmids with different sizes only by slightly adjusting the experimental conditions . Regarding the dynamic binding capacity of the arginine modified macroporous support it was achieved an improvement of more than 50 in the pDNA binding capacity when compared with their homologous arginine agarose commercial matrix suggesting potential economic feasibility in case of scale up .
|
Macroporous matrices present extremely good flow and binding capacity properties. Arginine macroporous support showed to be effective on the sc p53 pDNA isolation. The DBC achieved was 50 higher than its commercial homologous resin.
|
S0021967320300686
|
In this study three batches of nano titania functionalized covalent organic frameworks were acquired depending on different solvothermal reaction stages which were named as single roll up shaped nano titania functionalized COFs double roll up shaped nano titania functionalized COFs and clover shaped nano titania functionalized covalent organic framework respectively . After comparing their extraction performances the more efficient and stable CSTF COFs were selected as sorbent for the dispersive solid phase extraction of eight target N nitrosamines in drinking water followed by the determination with liquid chromatography tandem quadrupole mass spectrometry . Owing to the introduction of hydroxy groups CSTF COFs showed high extraction efficiency for N nitrosamines with a wide range of polarities through hydrogen bonding interaction hydrophobic interaction and hydrophilic interaction . Under optimum conditions the developed method provided relatively low limits of detection and satisfactory recoveries with relative standard deviations less than 8.3 . Therefore with the assistance of CSTF COFs trace levels of N nitrosamines were quantitatively and sensitively determined in 31 out of 460 bottled drinking water samples in a sensitive and convenient way .
|
Nano titania functionalized COFs were synthesized with ultrasound assistance solvothermal reaction. Eight N nitrosamines in drinking water were extracted by dSPE with CSTF COFs as sorbent. CSTF COFs could extract N nitrosamines with a wide range of polarities from drinking water. The dSPE method combined with LCMS MS was applied to the analysis of eight N nitrosamines ng L in drinking water samples.
|
S0021967320300698
|
We discuss how the efficiency of a chromatography device could be enhanced by incorporating a new feature which ensures flow uniformity . The overall flow of fluid within the device which has a cuboid shape could be visualized as a combination of two z patterns . The device is therefore designated as cuboid z
|
Improved cuboid packed bed device for efficient chromatographic separation. Novel flow arrangement for scalable uniform flow in chromatography device. Arrangement of flow at three levels of hierarchy. Superior performance with respect to older version of cuboid packed bed devices. Substantially superior performance than equivalent commercial column.
|
S0021967320300704
|
Seven retention models have been selected to describe a dual retention behavior of ten dopamine related compounds on polymer based monolithic stationary phase with zwitterion sulfobetaine functionality . Regression quality as well as a statistical significance of individual regression parameters have been evaluated . Better regression performance showed two four parameter models when compared to three parameter models . On the other hand limited number of experimental points disqualified statistical robustness of four parameter models . Among three parameter models retention description introduced by Horvth and Liang provided comparable quality of regression at significantly improved robustness .
|
Dual retention behavior of dopamine related compounds has been studied. Seven retention models were utilized to characterize retention. The model introduced by Horvth provided the most information. The polarity of the compounds has been predicted by using regression parameters. Regression parameters were used to characterize functional groups of tested compounds.
|
S0021967320300716
|
A green sample preparation method based on aqueous extraction followed by dispersive solid phase extraction with in situ derivatization was developed for the determination of aflatoxins in traditional Chinese medicines . AFs in TCMs were extracted by alkaline aqueous solution and converted to substituted coumaric acids . Then mixed mode anion exchange sorbent was used to isolate and enrich the substituted coumaric acids . During the elution by acetonitrile trifluoroacetic acid solution AFs were reconstructed and in situ derivatized . Several parameters affecting the procedure were evaluated . The developed preparation method coupled with high performance liquid chromatography fluorescence detection was successfully applied for AFs determination in TCMs . The limit of detection reached 10pg mL for AFs . Good linearity was obtained in three orders of magnitude with correlation coefficients ranging from 0.9996 to 0.9999 . The relative recoveries of the method were between 72.7 and 114.5 with intra and inter day relative standard deviations less than 9.5 and 10.1 respectively . The method was successfully applied to determine AFs in 15 kinds of TCMs in China with the results verified by IAC standard method .
|
Sodium hydroxide alkaline solution extraction of aflatoxins in 15 kinds of traditional Chinese medicines. MAX sorbents were used for extraction and in situ derivatization happened during elution. Detection limits was down to 10pg mL for AFs.
|
S0021967320300728
|
Baseline separation and analysis of multicomponent mixtures of closely related pharmaceuticals using single column selectivity can often be challenging requiring the combination of orthogonal stationary and mobile phase methods to monitor all the species and optimize reaction outcomes . In recent years two dimensional liquid chromatography has become a valuable tool for improving peak capacity and selectivity . Though powerful standard 2D LC instrumentation and software can often lead to tedious method development and has a requirement for very specific expertise that is poorly suited for a fast paced industrial environment . In this regard the introduction of an automated online 2D LC setup that could screen multiple columns in both dimensions without manual intervention will undeniably serve to streamline column mobile phase selection and secure the viability of 2D LC as a mainstay instrument for industrial applications . Herein we introduce and investigate a multicolumn online 2D LC approach that simplifies column screening and method development dramatically . This setup incorporates 6 position column selection valve technology whose functionality enables us to combine multiple columns in the first and second dimensions . This strategy in conjunction with diode array detection in both dimensions and mass spectrometry acquisition in the second dimension serves to explore different columns and mobile phases as a framework for screening targeted compounds in multicomponent mixtures without having to perform chromatographic purification . Multiple online heart cutting achiral RPLC achiral RPLC and achiral RPLC chiral RPLC coupled to DAD and ESI MS methods combining several stationary phase selectivity in an automated fashion are successfully applied to the separation and analysis of complex mixtures of drug substances where in many instances traditional 1D ultra high performance liquid chromatography fails or delivers sub optimal results . This automated online multicolumn 2D LC workflow enables rapid and efficient identification of column eluent combinations as well as sample analysis across multiple columns in both dimensions overnight with a single click .
|
Automated online multicolumn 2D LC streamlines rapid separation and analysis of closely related species. Heart cutting 2D LC using multiple columns in the second dimension as a framework for peak purity analysis. Multiple achiral chiral and achiral achiral online 2D LC DAD ESI MS enables method development and reaction monitoring among other applications. Multicolumn 2D LC allows for straightforward screening of targeted analytes in multicomponent mixtures without the need for purification
|
S002196732030073X
|
Complex chemical mixtures found in soils at contaminated sites typically includes polycyclic aromatic compounds thus posing potential environmental and human health risks . Pressurized liquid extraction followed by silica clean up is one of the most often used extraction methods for PACs in soil . While silica clean up provide satisfactory recovery of oxygenated polycyclic aromatic hydrocarbons this technique provides limited recovery of azaarenes . In this work we used PLE and in cell clean up with basic silica to increase the recovery of OPAHs and azaarenes . The optimized selective pressurized liquid extraction method used 4g basic silica dichloromethane 100 flush volume 100 and 120C extraction temperatures with two static cycles for each temperature no rinse in between the two extractions and 20 and 120s purge for the first and second extraction temperature respectively . The method was validated for a wide range of PAC groups including OPAHs azaarenes alkylated PAHs and sulfur heterocycles in total 87 PACs using certified reference material and in comparison to the results from previous inter laboratory data . Our SPLE method yielded results that are in agreement with certified values and inter laboratory data from prior analysis . The SPLE method also yielded lower variation than the results from the inter laboratory data for analysis of OPAH and azaarenes suggesting better precision than previous methods . More importantly the SPLE method increases sample analysis throughput as extra clean up step is not necessary anymore . The SPLE method was then successfully applied to rapidly screen PACs in three soil samples .
|
Selective pressurized liquid extraction method was developed to analyze PAC in soil. Spike and recovery experiment and CRMs were used to validate the method. The method was applied to analyze 87 PAC in three contaminated Swedish soils. Several toxic PAC often not analyzed in routine screening were measured in soil. The method can increase sample analysis throughput.
|
S0021967320300741
|
Volume overload is a critical limitation in Reversed Phase HPLC purification of pharmaceutical compounds . Limited solubility of these materials in most injection solvents leads to large injection volumes in order to maximize throughput . However peak distortion due to volume overload limits injection amounts and results in suboptimal use of chromatographic instruments . Volume loading for RP gradient separations was significantly increased by inserting a silica column ahead of the RP separation column . The sole purpose of this column is to dilute the plug of strong injection solvent so that the actual sample constituents are retained when the diluted injection plug arrives at the RP column . This is similar to the concept of a retention gap in GC yet this has never been applied to liquid chromatographic separations . Injection volumes were increased by almost a factor of 3 when using appropriately sized silica columns . A discussion of critical parameters that determine the effectiveness of this approach is provided . The concept is easily applied and does not require any system modifications . It is therefore well suited for open access applications where more instrument intensive approaches such as At Column Dilution would be less desirable . We will also show that the generic concept which we have titled In Column Dilution can easily be applied to increase the detection sensitivity for analytical application as well by allowing injection of larger sample volumes without peak deterioration for purifications .
|
Use of silica pre column significantly reduces impact of large volume injections in preparative reversed phase gradient purifications. In Column Dilution approach allows use of smaller columns for preparative purifications resulting in significant solvent and cost reduction. Injection volumes can be increased by a factor of three when using appropriately sized silica pre columns. In Column Dilution can also benefit analytical HLC analyses that require large volume injections.
|
S0021967320300777
|
During a microbial fermentation process the chemical composition of Fu brick tea changed substantially . To better profile the unique changes of metabolites and lipids in Fu brick tea at different fermentation stages a multifaceted strategy combining untargeted foodomics with UHPLC Q Orbitrap analysis was developed . The discriminative tea metabolites and lipids were determined by statistical analysis and online database matching . A total of 12 characteristic components were found to differ significantly among samples . Quantitative analysis showed that except for trimyristin and incensole acetate the content of these compounds gradually increased and finally stabilized with increasing fermentation time . The simultaneous determination of metabolites and lipids in this study provided detailed information for the analysis of multi component changes in a complex matrix .
|
Untargeted foodomics method enables both metabolites and lipids characterization. A variable data independent acquisition strategy was developed. Chemical component differences in distinct fermentation stages were analyzed. Dynamic changes during fermentation of Fu brick tea were revealed. The method was suitable to multi components profiling in complex matrix.
|
S0021967320300789
|
A novel column coupling approach is suggested to improve both the selectivity and efficiency of protein separations in liquid chromatography . Protein separations often suffer from limited selectivity or not appropriate resolving power . For a new biopharmaceutical product the identification of the main and minor variant species is required . For that purpose often offline collection fractioning is applied which is time consuming and regularly dilute the samples to an unacceptable extent . By serially coupling columns in the order of their increasing retentivity and applying multi isocratic elution mode indeed any selectivity can be attained . Moreover if a protein peak is trapped at the inlet of a later column segment of a coupled system its band will be refocused and elute in unprecedented sharp peak . Furthermore it becomes possible to perform online on column fractioning of protein species within a very short analysis time and without sample dilution . Two three or multiple column systems can be developed and applied for complex sample separations . This new methodology can be particularly useful to improve the analysis of therapeutic mAbs and related products and offers benefits compared to offline fractionating . It is also demonstrated in this proof of concept study that methyl modified RP phase has a great potential for protein separations despite it is not commercially available in state of the art wide pore superficially porous particle format ..
|
A novel column coupling approach is suggested for large solute separations. Widepore columns of different retentivity were selected for the coupling. The suggested approach improves both the selectivity and efficiency. On column protein fractioning can be rapidly performed.
|
S0021967320300790
|
Complexity and diversity of natural compounds make it a challenge for globally profiling constituents in multiple species plants especially for minor new compounds . Rubiaceae type cyclopeptides are one kind of active constituents and characteristic components in
|
A new multiple reaction monitoring strategy was developed for screening RAs in. 39 RAs including 19 new RAs have been determined by LC MS for the first time. 7 RAs markers were found to distinguish. and
|
S0021967320300819
|
A novel chiral stationary phase was prepared through the reaction of surface initiated atom transfer radical polymerization by the copolymerization of thermoresponsive
|
A smart thermoresponsive CSP was prepared by copolymerization of cyclodextrin and. isopropylacrylamide. The hydrophobicity and hydrophilicity of CSP can be switched by changing column temperature. The enantioselectivity of enantiomers can be modulated on the chiral column. The prepared column could further be used to separate benzene compounds.
|
S0021967320300820
|
Retention time shifts in second order calibration assisted chromatographic analysis seriously impact the modeling and quantitative accuracies in complex systems . In this work three second order methods i.e . alternating trilinear decomposition algorithm multivariate curve resolution alternating least squares alternating trilinear decomposition assisted multivariate curve resolution were compared their performance to process liquid chromatographic data in the presence of retention time shifts and overlapped peaks . Firstly the validation samples contain five tea polyphenols at three concentrate levels within the calibration ranges helped to understand visualize and interpret these features of three second order multivariate methods . Secondly experimental data were studied concerning the determination of polyphenols in Chinese tea samples by HPLC DAD . The results showed that all three second order multivariate methods realized satisfactory quantification for five targeted analytes in Pu Er ripe tea samples and Green tea samples even with the interference of slight retention time shifts average recoveries were 91.23 113.16 for ATLD 89.96 115.96 for ATLD MCR 90.64 117.60 for MCR ALS respectively . However ATLD was disappointing in the case of larger time shifts occurring for the quantitative analysis of Black tea and Clinacanthus nutans tea the average recoveries were just 67.3384.05 . Relatively MCR ALS and ATLD MCR were more significantly excellent satisfactory results still can be obtained the average recoveries for MCR ALS and ATLD MCR were in the range of 86.04117.60 and 89.96115.96 respectively .
|
Second order chromatographic data with retention time shifts is investigated. ATLD MCR and ATLD MCR are compared. The scope of time shifts for correctly data processing by three methods is studied. The experimental data are studied to quantify tea polyphenols in Chinese tea.
|
S0021967320300832
|
The aim of our work was to develop an analytical strategy to quantify naphthalene acenaphthylene acenaphthene fluorene phenanthrene and anthracene in fish products by on line dynamic headspace extraction followed by thermodesorption injection and gas chromatography analysis coupled with tandem mass spectrometry using electron ionization mode . The developed protocol used 1g of freeze dried or oil sample supplemented with perdeuterated light PAHs . The sample was heated at the headspace of the sample was swept by nitrogen and the trapping of the PAHs was carried out on a Tenax type adsorbent placed at 25C . Analytes were thermodesorbed at 300C from the dried adsorbant and then cryofocused on a cooled injection system at 25C before injection 12Cs
|
A DHS TDU GC MS MS method was developed to quantify light PAHs in seafood. Two methods are now available one is more accurate and the second more robust. Validation was performed to determine measurement uncertainties at 120 ngg. dw. A first occurrence level was measured in around 200 seafood samples.
|
S0021967320300844
|
This work extends the present working range of isotachophoresis with electrospray ionization mass spectrometric detection and describes for the first time a functional cationic electrolyte system for analyses at medium alkaline pH . So far no ITPMS application was published on the analysis of medium strong bases although there is a broad spectrum of potential analytes like biogenic amines alkaloids or drugs where this technique promises interesting gains in both sensitivity and specificity . The presented results include a selection of suitable sufficiently volatile ESI compatible system components discussion of factors affecting system properties and recommendations for functional ITP electrolyte systems . Theoretical conclusions based on calculations and computer simulations are confirmed by experiments with a model mixture of beta blockers . Practical applicability of the method is demonstrated on the example of analysis of sotalol in dried blood spots where direct injection of aqueous extract ITP stacking and MS detection provide a fast simple and sensitive technique with limits of quantitation on the sub nM level .
|
First reported cationic ITPMS in alkaline medium. Electrospray compatible electrolyte systems. Simple fast and sensitive analysis of cationic beta blockers. Sub nM analysis of sotalol in dried blood spot extracts.
|
S0021967320300856
|
An expression for peak compression factor based on temporal peak widths is proposed which can be measured directly . The relationship between it and peak compression factor based on spatial peak widths is given . The experimental data presented in the Neue s work are reevaluated . The peak compression factor is recalculated by taking into account the curvature in the plot of logarithmic retention factor ln
|
A peak compression factor. based on temporal peak widths is proposed. The variation in plate number. with mobile phase composition. is considered. The curvature in the plot of logarithmic retention factor ln. vs. is considered. The discrepancy between experimental and predicted values of. is reduced. The relationship between. s obtained under ideal and real situation is given.
|
S0021967320300868
|
Peptide retention time prediction models have been developed for zwitter ionic ZIC HILIC and ZIC cHILIC stationary phases using proteomics derived retention datasets of 30 thousand tryptic peptides each . Overall hydrophilicity of these stationary phases was found to be similar to the previously studied Amide HILIC phase but lower compared to bare silicas . Peptide retention is driven by interactions of all charged residues at pH 4.5 but shows specificity according to orientation of functional groups in zwitter ionic pair . Thus ZIC cHILIC exhibits an increased contribution of negatively charged Asp and Glu due to the distal positioning of positively charged quaternary amines on the stationary phase . These findings confirm that HILIC interactions are driven by both peptide distribution between water layer adsorbed on the stationary phase and by interactions specific to functional groups of the packing material . Sequence Specific Retention Calculator HILIC models were optimized for these columns showing 0.9670.976 R
|
Sequence dependent peptide retention prediction model developed for zwitter ionic columns. Peptide retention at pH 4.5 is mostly driven by charged residues Arg Lys His Asp Glu. Different zwitter ionic pair result in different contribution of charged residues for retention.
|
S0021967320300881
|
High performance liquid chromatography methods with UV vis detection are the most widespread analytical procedures in modern pharmaceutical applications but reach their limitations when it comes to non chromophore molecules . Hence instead of using tiresome derivatization procedures many liquid chromatography methods make use of the so called aerosol based universal detectors namely the evaporative light scattering detector the condensation nucleation light scattering detector and the charged aerosol detector . Amongst these the CAD being the youngest of these three options is often described as the most easy to use detector and is stated to exhibit sufficient sensitivity and good linearity of signal in a dedicated range of concentration . Therefore this review sets its focus on the recent applications of the CAD for active pharmaceutical ingredients excipient analysis as well as botanical applications . Alongside the post column solvent addition techniques the new CAD s ability to adjust the evaporation temperature and the possibility to use an integrated power function for signal linearization are reviewed as previously unavailable new parameters for optimization .
|
Recent analytical applications of the charged aerosol detector are presented. Adjustable parameters of the charged aerosol detector are presented and discussed. Signal generation characteristics of the charged aerosol detector are discussed.
|
S0021967320300893
|
Solvent Front Position Extraction procedure has been recently introduced as a novel concept for multi component sample preparation . According to the procedure thin layer chromatography is used to separate the compounds of interest from matrix components and to focus them into a common zone from which the compounds are extracted and transferred to apparatus for instrumental analysis . In the paper we investigate different adsorbent types of the chromatographic plates and various mobile phases including pH of their buffers in respect of optimization conditions of the SFPE procedure . The research was carried out using a test sample containing 9 compounds characterised by different chemical properties hence the conclusions from the obtained results can be applied to other multi component samples . Under the optimal conditions all target compounds are separated from other compounds and evenly distributed along a narrow strip which is advantageous for their quantitation . The determination results are good the percentage values of relative error and relative standard deviation do not exceed 6 .
|
TLC is applied to sample preparation for quantitation with instrumental technique. Optimisation of the procedure conditions of the sample preparation is shown. Nine components of various properties can be quantified with the procedure. The final sample is cleaned from matrix components.
|
S002196732030090X
|
Traditional boron affinity materials usually capture cis diol containing molecules under alkaline condition but some cis diol containing molecules such as polyphenols are unstable and easy to be oxidized and degraded under alkaline condition . Teamed boronate affinity can specifically capture cis diol containing molecules under neutral condition . However the report about combination of TBA and magnetic nanoparticle for the extraction was rare . Here we fabricated two kinds of teamed boronate affinity magnetic nanoparticles including
|
Teamed boronate affinity TBA can specifically capture cis diol containing molecules under neutral condition. TBA magnetic nanoparticles TBAMP was fabricated for capturing polyphenols under neutral condition. TBAMP was used for magnetic solid phase extraction MSPE of 13 kinds of polyphenols. MSPE combined with HPLC MS was used to detect polyphenols from Flos Lonicerae Beverage.
|
S0021967320300911
|
Recently ion chromatography coupled with mass spectrometry has been used for the determination of anionic metabolites . However connection with a mass spectrometer in this method is not straightforward because backpressure produced by the addition of a make up solution often affects the peak resolutions of the target metabolites . To overcome this problem we developed a capillary ion chromatography mass spectrometry method utilizing a double coaxial electrospray ionization sprayer . This method was not affected by backpressure and the number of theoretical plates was about three times that of a conventional sprayer . Under optimized conditions 44 anionic metabolites including organic acids sugar phosphates nucleotides and cofactors were successfully separated and selectively detected with a Q Exactive mass spectrometer . The calibration curves of the tested metabolites showed excellent linearity within the range of 1100 000nmol L and the correlation coefficient was greater than 0.991 . The detection limits for these metabolites were between 1 and 500nmol L . The developed method was applied to the quantitation of anionic metabolites in cultured cancer cell samples with tumor necrosis factor stimulation . This allowed for the successful determination of 105 metabolites . The levels of tricarboxylic acid cycle intermediates changed significantly after TNF stimulation . These results demonstrate that the developed method is a promising new tool for comprehensive analysis of anionic metabolites .
|
A double coaxial electrospray ionization sprayer improves the peak resolutions. This method is highly selective and sensitive for anionic metabolites. This method is suitable for non targeted analysis of anionic metabolites.
|
S0021967320300923
|
Considering the huge difference of biological toxicity it is extremely significant to recognize the exact content of arsenic species in actual samples . In this paper a novel pretreatment technique for the efficient extraction of arsenic species from herbal samples is developed by dual frequency ultrasound assisted enzymatic digestion . The preservation of arsenic original form reduction of the actual analysis time environmental friendliness and free interference in subsequent detection make this method over the traditional method such as wet digestion ashing and some solvent extraction technologies . The combination of DUED and atomic fluorescence spectrometry realize the speciation analysis of arsenic in traditional Chinese medicine . The optimizations of experimental parameters have been achieved and the potential mechanism is discussed . The experimental data showed that cellulase is suitable for the digestion of herbal matrix than amylase and papain . Ultrasound can significantly increase the rate of enzymatic hydrolysis of biological molecules especially under dual frequency ultrasound irradiation . The highest relative extraction efficiency can be obtained by combining 40kHz ultrasonic bath with 20kHz ultrasonic probe . Two certified reference materials 090066 and GBW090067 and four practical herbs were used to evaluate the accuracy and practicability of the method . Inorganic arsenic including trivalent arsenic and pentavalent arsenic was the main species in the four herbal samples .
|
Dual frequency ultrasound assisted enzyme extraction technology can effectively extract and maintain the initial form of arsenic. Cellulase is more suitable for extracting arsenic species from herbal matrix samples. The application of dual frequency ultrasound can shorten the sample processing time to 6min.
|
S0021967320300935
|
Disinfection by products in drinking water can pose a health risk to humans . In this work a new nitrogen rich covalent organic frameworks was synthesized and applied firstly as a novel solid phase extraction trapping media for four ultra trace levels of DBPs in drinking water samples . Under the optimal conditions these DBPs were absorbed on a SPE cartridge then the DBPs were eluted with the optimized volume of eluent . The concentrated elution was detected and quantified by gas chromatography mass spectrometry . Low limits of detection 0.00040.0063ng mL
|
Novel TpTt COFs with high chemical stability were synthesized and used as SPE materials. TpTt COFs achieved superior enrichment performance towards DBPs. TpTt COFs was used for the enrichment and analysis of DBPs in drinking water.
|
S0021967320300947
|
A method for sample pretreatment using liquid liquid chromatography combined with a conventional liquid chromatography was developed for quantitative determination of trace chemical component in traditional Chinese medicine . The main effective component wilforlide A in the traditional Chinese medicinal herb
|
Liquid liquid chromatography was studied in sample pretreatment for quantification. Continuous stirred tank reactors model was used to predict collection time of analytes. Determination of wilforlide A in. and tablets was established. A new method for sample pretreatment in analysis of trace component was developed.
|
S0021967320300959
|
The anionic phospholipid class of cardiolipins is increasingly attracting scientific attention in the recent years . CL can be found as a functional component of mitochondrial membranes in almost all living organisms . Changes in the CL composition are favored by oxidative stress . Based on this finding the investigation of CL and their oxidation products in relation to various disease patterns including neurodegenerative ones is moving into the focus of current research . The analysis of this diverse lipid class is still challenging and requires sensitive and selective methods . In this work we demonstrate an online two dimensional liquid chromatography approach by means of a heart cut setup . In the first dimension a fast hydrophilic interaction liquid chromatography method was developed for the separation of CL and their oxidation products from other phospholipid classes but more important from nonpolar lipid classes such as triacylglycerol and cholesterol . Those classes can negatively affect the electrospray ionization and also the chromatography . For the heart cut approach the CL fraction was selectively transferred to a loop using a six port valve followed by the transfer to a reversed phase column in second dimension . On the RP column the transferred CL fraction including the oxidation products were separated according to the hydrophobicity of acyl chain moieties . Matrix effects were significantly reduced compared to the one dimensional LC MS method . In addition the total separation time had not to be prolonged by shifting the equilibration step of the RP column parallel to the separation in first dimension . The heart cut LC LC approach was applied to artificially oxidized lipid extracts of bovine heart and yeast by means of Fenton reaction . In summary 42 species have been identified by high resolution mass spectrometry and database matching . 31 species thereof have been further characterized by MS MS experiments .
|
Analysis of cardiolipins and their oxidation products by online two dimensional HILIC RP LC MS. Efficient HILIC separation of phospholipid classes in first dimension and removal of nonpolar lipid classes. Increased sensitivity due to less matrix effects for cardiolipins and oxidized species. Separation of isomeric cardiolipin oxidation products in second dimension. Cardiolipin characterization by accurate mass database matching using MZmine 2 and MS MS fragmentation.
|
S0021967320300960
|
One of the most important causes of the high mortality rate and low life expectancy of lung cancer is the detection at advanced stages . Thus there is an urgent need for early diagnosis and the search of new selective biomarkers . Selenium is an important constituent of selenoproteins and a powerful antioxidant able to protect against cancer . In this work the absolute quantification of selenium in selenoproteins and the total content in selenometabolites has been performed for the first time in serum from lung cancer patients and healthy controls . To this end a method for the simultaneous speciation of selenoproteins using size exclusion chromatography and affinity chromatography with detection by ICP QQQ MS and quantification by isotopic dilution was developed to determine the selenium concentration in eGPx SEPP1 and SeAlb as well as total selenometabolites to find alterations that may serve as biomarkers of this disease . In the same way a method based on anion exchange chromatography coupled to ICP QQQ MS was developed to quantify selenometabolites in the same LC and HC serum samples . The results showed that the averaged concentrations of selenium in eGPx SeAlb and selenite were significantly higher in LC patients LC eGPx 21.240.77ngg
|
Selenoproteins have been quantified for the first time in lung cancer patients. A new column switching system coupled to ICP QQQ MS has been validated and is a reliable method. Significantly different concentrations and ratios of selenoproteins were found. Correlations were found among selenoproteins and between total selenometabolites. Results demonstrated the interconnected homeostasis between selenoproteins
|
S0021967320301151
|
This work presents a new triptycene based stationary phase combining the three dimensional triptycene framework with polyethylene glycol moieties for gas chromatographic separations . Its statically coated capillary column showed high column efficiency of 5263 plates m determined by naphthalene at 120C . Its Rohrschneider McReynolds constants and Abraham solvation system constants were measured to characterize its polarity and molecular interactions with analytes of different types . As evidenced the TP PEG column showed high resolution performance for the isomers of anilines phenols halobenzenes and alkanes with distinct advantages over the PEG columns particularly those critical isomers such as 3 5 2 3 xylidine
|
Combining the 3D rich TP framework with polar PEG moieties. High resolution performance for the isomers of anilines phenols and alkanes. Low operational temperature and improved thermal stability. Good potential for analysis of essential oils.
|
S0021967320301163
|
A simple green and efficient method for extraction purification and enrichment of pesticide residues of triazoles and pyrethroids in Longan fruit was developed by ultrasonic assisted aqueous two phase extraction coupled to vortex assisted dispersive liquid liquid microextraction . Using an aqueous two phase system of ethanol K
|
A simple and green method for sequential extraction of pesticides by UAATPE coupled to VADLLME. UAATPE extraction of pesticide residues with ethanol K. HPO. system as extractant. 1 dodecanol as solidification extractant for VADLLME enrichment and separation of pesticides. Connecting UAATPE with VADLLME by using ethanol as a co reagent without extra steps. Determination of pesticide residues in Longan fruits from different districts by HPLC DAD.
|
S0021967320301175
|
A new stationary phase based on glucose derived carbon dots modified on silica was prepared and applied in hydrophilic interaction chromatography . The Sil Glc CDs column showed better retention ability and separation selectivity toward polar analytes including amino acids saccharides ginsenosides antibiotics nucleosides and nucleobases when compared with a commercial HILIC column and a home made glucose modified silica column . The effect of the organic phase ratio salt concentration pH and column temperature on chromatographic retention behavior was investigated . In addition the column exhibited good stability and column to column reproducibility RSDs 0.801.97
|
Glucose based carbon dots modified silica packing material was prepared. Good separation performance for HILIC was obtained. Amino acids saccharides ginsenosides antibiotics nucleosides and nucleobases were separated. Quantitative detection of mono saccharides in goji berry solution was obtained.
|
S0021967320301187
|
Hydrophilic Interaction Liquid Chromatography is a technique for retaining polar analytes that uses polar stationary phases and acetonitrile rich mobile phases . While this technique has several advantages over reversed phase liquid chromatography one main drawback is the reported need for longer column equilibration . The reason for this is not fully understood and is a topic of current investigation . In order to better understand and reduce the equilibration needs accurate characterization of column equilibration under varying conditions is required . The current method of characterizing HILIC column equilibration produces limited data points per test or low time resolution and is highly dependent on the column and probe compounds being used . There is a need for an improved method for characterizing HILIC column equilibration especially if trends across stationary phases are to be observed . In this work MISER or Multiple Injections in a Single Experimental Run is evaluated as a possible tool for characterizing HILIC column equilibration . MISER improves time resolution by allowing for replicate injections without interruption of data collection enabling a more thorough evaluation of column equilibration compared to traditional techniques . Experimental results gathered using MISER show that equilibration of a BEH Amide column is notably shorter when equilibrating from acetonitrile to mobile phases containing higher percentages of water . Column equilibration to a 10 aqueous mobile phase was found to be approximately 5 fold faster than equilibration to a 3 aqueous mobile phase .
|
Evaluation of MISER for use in HILIC column characterization. Characterization of one HILIC column using three different mobile phases. Percentage water in the mobile phase drastically effects column equilibration.
|
S0021967320301199
|
Although various cyclodextrins have been utilized to prepare organic polymer based monolithic columns there were few reports on fabrication of cyclodextrin functionalized hybrid monolithic columns . Herein a sulfobutylether cyclodextrin silica hybrid monolithic column was prepared by one step method via the co polymerization of hydrolyzed organosiloxane precursors and glycidyl methacrylate sulfobutylether cyclodextrin . The morphologies of prepared monolithic columns were observed by optical microscopy and scanning electron microscopy . The sulfobutylether cyclodextrin was incorporated into the polymeric structure which was demonstrated by energy dispersive X ray spectroscopy Fourier transform infrared spectroscopy spectrum and X ray photoelectron spectroscopy . The resulting columns were used for chiral separations of twenty six racemic compounds and satisfactory separation selectivity was obtained . Compared with other two kinds of neutral cyclodextrin based hybrid monoliths sulfobutylether cyclodextrin silica hybrid monolith showed superior chiral resolution . These results demonstrated the sulfobutylether cyclodextrin silica hybrid monolithic column was promising in chiral compounds analysis .
|
A novel sulfobutylether cyclodextin SBE CD silica hybrid monolithic column was prepared. The SBE CD silica hybrid monolithic column has superiority over neutral cyclodextin based hybrid monolithic columns in CEC enantioseparation. The SBE CD hybrid monolith was suitable for enantioseparation of basic analytes.
|
S0021967320301205
|
Poly and perfluoroalkyl substances have been investigated in a number of cohort studies due to concern over their adverse health effects . The aim of this study was to develop a reliable high throughput and cost effective analytical method for a broad range of PFAS in human serum . Protein precipitation automatic solid phase extraction pre treatment and column switching LC MS MS were employed . The optimised and validated method was then used to analyse the levels of 28 PFAS in 339 maternal serum samples from Pilot Study of the Japan Environment and Children s Study . Perfluorooctanoic acid perfluorononanoic acid perfluoroundecanoic acid and perfluorooctane sulphonic acid were detected in all 339 samples at median concentrations of 1.9 1.5 1.3 and 3.7 ng ml respectively . These levels are comparable to those reported in previous studies using samples collected from various parts of the world . With a few exceptions the remainder of the PFAS examined had lower detection rates but were found at concentrations similar to those reported in previous studies . The sensitivity and throughput ability of the method developed here are sufficient for its application in a large scale biomonitoring study .
|
An on line SPE LC MS MS method was developed for 28 PFAS in human plasma serum. The method had sufficient sensitivity and throughput for a large scale study. The method was used for the Japan Environment and Children s Study JECS . The PFAS levels in this study were similar to those reported in previous studies.
|
S0021967320301217
|
Peptide N glycosidase F is the most frequently used enzyme to release N glycan from glycoproteins in glycomics however the releasing process using PNGase F is tedious and can range in duration from hours to overnight . Recently efforts have been made to accelerate this enzymatic reaction and they include the use of microwave irradiation ultrahigh pressure enzyme immobilization and other techniques . Here we developed a novel method combining the oriented immobilization of PNGase F on magnetic particles and microwave assisted enzymatic digestion techniques to achieve highly efficient release of N glycans . The oriented immobilization of PNGase F on magnetic particles utilizes the affinity of its co expressed His tag towards iminodiacetic acid Nickel modified magnetic particles . Compared with non oriented immobilization the oriented immobilization of PNGase F exhibits several advantages including tolerance to high temperature and the ability to retain strong activity after more than five reuses . When used in combination with microwave irradiation efficient N glycan removal from ribonuclease B was achieved within 5min . The proposed strategy was also used to release glycan from fetuin and human serum and has proven to provide a promising deglycosylation method for the characterization of protein glycosylation .
|
PNGase F containing histidine tag is expressed in the form of inclusion body to increase its production and purity. Oriented immobilization of PNGase F using the affinity of its co expressed His tag towards iminodiacetic acid Nickel modified on the magnetic particles improves the loading capacity thermostability deglycosylation efficiency and repeatability. Assisted with microwave irradiation N glycan removal from ribonuclease B by oriented immobilization of PNGase F can be achieved within 5min.
|
S0021967320301229
|
An enhanced fluorescence detection system of capillary electrophoresis was equipped with a concave silver mirror by which the detection sensitivity of light emitting diode induced fluorescence can be increased greatly . The silver concave mirror and the cathode window in photomultiplier tube were accurately set face to face at the same axis . When the two labeled tumor markers exactly moved to the center of detection window the emission from analytes are excitated by LED source . Currently the analytes may be regarded as a luminescent source point . When the source point exactly moves to the focus of the concave mirror the emission of the labeled sample was collected effectively enhanced by convergence and reflected by the concave mirror . Then it was sensitively detected by the PMT . The optical mechanism of enhancing detection sensitivity was explored . A simple comparative test on sensitivity was carried out which aimed to compare sensitivity of the new detection system with concave mirror to that without concave mirror but the other conditions were kept the same . Two tumor markers labeled with FITC were selected for the test using the simple LEDIF detect system . The results showed that the detection sensitivity matched with concave mirror reached more 16 times than the detection method without concave mirror .
|
An enhanced FL detection system of CE was designed with a concave silver mirror. The optical mechanism of enhancing sensitivity was explored with CSM LEDIF. The sensitivity was demonstrated by quantitative detection for two tumor markers. The detection system can be used for increasing sensitive detecting of LEDIF.
|
S0021967320301230
|
Multi column periodic counter current chromatography has been developed for continuous antibody capture but the complexity of continuous processes makes experimental optimization time consuming and costly . In this work with twin column continuous system as a typical case mathematical models were established and used to evaluate the impacts of operating parameters for process development . The model fitted well with the experimental breakthrough curves and process performance under varying protein concentrations and residence times . Three important operating parameters residence time for interconnected feeding
|
A mechanistic model was developed to predict breakthrough curves and continuous process performance. Effects of key operating parameters on continuous capture were evaluated systematically. Three phase process performance was found for twin column continuous capture. Model based design approach was proposed for continuous capture process development.
|
S0021967320301254
|
This work presents and evaluates an algorithmic approach to deconvolving the elution profiles of chemical components of vapor mixtures that have been sampled and desorbed from a novel preconcentrator based on highly ordered silicon nanowire arrays . The arrays provide a medium for both preconcentration and partial chromatographic resolution which is then further leveraged with multichannel detection . Here mixtures of nitro aromatic vapors are sampled and then thermally desorbed from the device at which point they are detected by a conventional mass selective detector . The overlapping elution profiles observed from the array are sequentially extracted using a chemometric analysis approach based on evolving factor analysis and multivariate curve resolution by alternating least squares enabling qualitative and quantitative analysis of individual components without target analyte libraries or complete chromatographic separation . This work examines the analytical capabilities conferred to multichannel detection by silicon nanowire array pre concentration and partial separation and discusses the technique s limitations illustrated by both experimental and simulated data .
|
Silicon nanowire arrays provide a medium for preconcentration and separation of vapor mixtures. Multivariate curve resolution is sequentially applied to extract overlapped elution profiles and spectra. Non target qualitative analysis of nitroaromatic vapor mixtures is demonstrated.
|
S0021967320301266
|
Glyphosate and glufosinate are widely used herbicides around the world and their effects on human health and detection of levels have drawn increasing attention . The present study was to establish a method to determine the contents of Glyp and Gluf from corn using multi walled carbon nanotubes followed by ultra high performance liquid chromatography tandem mass spectrometry . The corn samples were purified by MWCNTs then the analytes reacted with 9 fluorenylmethylchloroformate FMOC
|
Simultaneous detection of glyphosate and glufosinate. Using multi walled carbon nanotubes as purification. The procedures are simplified and the determination time is 4min. The matrix effect was reduced by purification internal standard and dilution. The analytical method has good recovery linearity precision LOD and LOQ.
|
S0021967320301278
|
Protein adsorption plays a role in many fields where in some it is desirable to maximize the amount adsorbed in others it is important to avoid protein adsorption altogether . Therefore theoretical methods are needed for a better understanding of the underlying processes and for the prediction of adsorption quantities . In this study we present a proof of concept that the calculation of protein adsorption isotherms by molecular dynamics simulations is possible using the steric mass action theory . Here we are investigating the adsorption of bovine human serum albumin and hemoglobin on Q Sepharose FF . Protein adsorption isotherms were experimentally determined and modeled . Free energy profiles of protein adsorption were calculated by MD simulations to determine the Henry isotherms as a first step . Although each simulation contained only one protein notably the calculated isotherms are in reasonably good agreement with the experimental isotherms . Hence we could show that MD data can lead to protein adsorption data in good agreement with experimental data . The results were critically discussed and requirements for future applications are identified .
|
Free energy profiles of protein adsorption were calculated by MD simulations. MD combined with the SMA theory is used to calculate protein adsorption isotherms. Protein adsorption isotherms on Q Sepharose FF were experimentally validated. Proof of concept that this combination has potential for isotherm predictions.
|
S002196732030128X
|
Carbohydrates are a class of important water soluble organic compounds in atmosphere . In this study a high performance liquid chromatography tandem mass spectrometry was applied to characterize carbohydrates in aerosol particles . Since carbohydrate was a kind of compound with low response in mass spectrometry the conventional HPLC MS MS method was not sensitive enough to determine it . When acetate acid was added into mobile phase as buffer the transition of M CH
|
A sensitive method based on HPLC MS MS was developed to determine carbohydrates in atmosphere. This may be the first time to attach CH. COO. to 2 Methylbutane 1 2 3 4 tretraol using HPLC MS MS. There is no need to separate carbohydrates completely in SRM scan mode. The LODs of carbohydrates may be the lowest in HPLC MS MS methods.
|
S0021967320301308
|
Increasing molecular diversity and market competition requires biopharmaceutical manufacturers to intensify their processes . In this respect frontal chromatography on cation exchange resins has shown its potential to effectively remove aggregates . However yield losses during the wash step need to be accepted in order to ensure robust product quality . In this work we present a novel counter current frontal chromatography process called Flow2 which uses inline dilution during an interconnected wash phase to allow high monomer recovery without contaminating the product pool with impurities . Its model based design spaces under purity and yield constraints are compared with those corresponding to traditional batch processes in terms of size and process attributes yield and productivity . The Flow2 process shows the largest extent of feasible operating points independent of feed conditions . Thereby it allows the implementation of higher ionic strength wash thus widening the range of operating conditions resulting in yields above 95 compared to batch processes . Productivities of batch and counter current processes are the same at short regeneration times and equal residence time . However long regeneration times while influencing the size of the Flow2 design space are not detrimental for its productivity resulting in twice as high values as obtained for the batch process . Furthermore process robustness is evaluated by the ability of the process to maintain the required product quality when subjected to process parameter perturbations . It is found that the Flow2 process is able to retain a larger design space associated also with higher yields showing its ability to improve process attributes without sacrificing robustness at the same time .
|
Novel two column counter current frontal chromatography process is presented Flow2. Model based design spaces are established for counter current and batch processes. Design spaces reveal higher operational flexibility of the counter current process. Perturbation studies reveal increased robustness of the counter current process.
|
S002196732030131X
|
Quality assessed analytical methods are required to determine organic priority substances in biota for the monitoring of the water status according to the EU Water Framework Directive . Although the literature describes several analytical methods to determine these substances in fish discussion about the efficiency of the clean up procedures to remove the lipids in the final organic extract is scarce . This work highlights the results of the development of an analytical method for organochlorines in fish tissue focused on the optimisation of the clean up step in order to obtain a final extract with the lowest amount of lipids . The efficiency of the purification of the final extract was assessed by quantifying the removal of co extractives gravimetrically by considering the sensitivity of the gas chromatography mass spectrometry method for the analytes and by assessing the analytes recovery . An analytical method based on accelerated solvent extraction followed by gel permeation chromatography and dual solid phase extraction and quantification via isotope dilution GCMS was applied to the analysis of seven PS isomers pentachlorobenzene hexachlorobenzene and hexachlorobutadiene . A preliminary validation of the method was carried out with satisfactory results for all analytes in terms of intermediate precision . Repeatability values were satisfactory for HCH PeCB and HCB while the obtained results for HCH and HBCD showed the need for further optimisation . Trueness was within the target performance for all analytes except and HCH . Limits of quantification between 0.5 and 3.3ng g wet weight were achieved depending on the analytes . The proposed method can be employed to determine the mentioned PS in fish tissue with up to approximately 6 lipid content . The presented results show the challenges in establishing an analytical method which aims at balancing the required accuracy with the routine applicability as needed in the context of environmental monitoring .
|
Organochlorine substances are determined in biota by ASE GPC dual SPE and GC IDMS. Successful removal of the co extractives from the fish matrix was achieved. Combination of multiple clean up steps is required to obtain a fat free extract. Analytes recovery and GC MS sensitivity were optimised. Validation of the method for and HCH PeCB HCB and HCBD was accomplished.
|
S0021967320301321
|
A new platform was developed for determination of drugs in plasma without extraction or instrumental analysis just using TLC smart phone digital camera and free image processing software . Lamotrigine antiepileptic drug was used as model analyte . The proposed platform depends on using oil in water microemulsion to isolate the drug from plasma proteins and using water in oil microemulsion as mobile phase for TLC which results in complete separation between lamotrigine and plasma as viewed under UV lamp . The composition of both microemulsions was optimized using Taguchi orthogonal array and Plackett Burman design . The optimal microemulsion predicted composition was 0.01mL Butyl acetate 4mL butanol 0.925 gm SDS and 8.6mL water while the mobile phase microemulsion was 9mL Butyl acetate 1mL butanol 0.25 gm SDS 0.25mL water . Separation was carried out on a silica gel 60F 254 plate eluted with the microemulsion in about 30min development time . The images of TLC plates were processed using 4 different programs by comparing their results it was found that integrated density measured by
|
Oil in water microemulsion dissolved plasma proteins as sample pretreatment step. Water in oil microemulsion mobile phase separated plasma and lamotrigine on TLC plate. Image processing detected the concentration of lamotrigine directly on TLC plate. Both microemulsions were optimized using different experimental designs. Lamotrigine was determined in plasma without extraction or instrumental analysis.
|
S0021967320301333
|
Emulsifiers of the type E472 are esters of fruit acids and mono and diacylglycerols which are used to adjust techno functional properties in various food products . The most dominant representatives of E 472 emulsifiers are acetic acid esters lactic acid esters citric acid esters and mono and diacetyl tartaric acid esters . For the determination of fruit acids a high performance liquid chromatography method with ultraviolet light detection was developed . Free and total fruit acids were determined by reversed phase HPLCUV analysis of untreated and saponified emulsifier extracts with 20mM potassium hydrogen phosphate buffer as isocratic eluent . Limits of quantitation of 0.080.27g free fruit acid kg emulsifier and 414g total fruit acid kg granted a reliable method with recoveries for free and total fruit acids between 80 and 100 with relative standard deviations
|
A characterization for E 472 food emulsifiers was performed. HPLC with sensitive ultraviolet light detection was performed. Free and total fruit acids were determined. Quantitation of free glycerol with an enzymatic assay was optimized. The ash content was determined by dry ashing.
|
S0021967320301345
|
A simple portable and battery powered trapping device consisting of a purification tube a trapping unit and a miniature air pump was developed for the pre concentration of volatile organic sulfur compounds . The tested VOSCs including methanthiol ethanethiol dimethyl sulfide diethyl sulfide and dimethyl disulfide were firstly purged from water samples and then
|
A portable and battery powered trapping device was fabricated for. preconcentration of VOSCs. The disadvantages associated with conventional sample storage methods for VOSCs analysis was overcome. Long term preservation of VOSCs could be accomplished. collection with the developed trapping device. Twenty six adsorbents were studied to find the most suitable adsorbent for the tested VOSCs.
|
S0021967320301357
|
In this study an online capillary electrophoresis based dual enzyme co immobilized microreactor was constructed for studying enzyme kinetics and screening dual target inhibitors against THR and FXa with the aid of the polydopamine graphene oxide coating . Based on the developed THR FXa IMER the Michaelis Menten constants
|
An online CE based THR FXa IMER with good stability and repeatability is developed. The prepared IMER is applied to screen dual target inhibitors against THR and FXa. Molecular interaction between enzyme inhibitor is verified via molecular docking. A new structure with high inhibition activity is theoretically found by scaffold hopping
|
S0021967320301369
|
In this work a dispersive solid phase extraction method for sulfonamides has been developed using a stable and mesoporous metal organic framework as adsorbent which was synthesized by coordination of Zr
|
A high performance d SPE method for sulfonamides was established. The synergistic effect of interaction hydrogen bonding and size match was involved. The adsorption mechanism was studied by using kinetic models. The pore size of UiO 67 showed high match with molecular diameters of sulfonamides.
|
S0021967320301370
|
It is necessary to establish a rapid simple and environmentally friendly detection method for benzoylurea pesticides in environmental water samples because of their toxicity in environmental circulation . Herein a novel polyethylene glycol modified magnetic covalent organic framework material based on the Schiff base reaction was prepared PEG Fe
|
This material PEG Fe. @SNW 1 was used in magnetic solid phase extraction for the first time. PEG 600 modified magnetic nanoparticles could decrease the aggregation rate and improve the chemical stability. Sufficient accuracy precision and sensitivity of the proposed method were achieved for detecting benzoylurea pesticides.
|
S0021967320301382
|
The mixed mode chromatographic behavior was estimated for imidazoline and serotonin receptor ligands and their related compounds on dual hydrophilic reversed phase stationary phase . The Box Cox transformation was used to obtain the most suitable mathematical equations which describe the mixed mode retention . Optimal equations were found for the optimization parameter
|
Mathematical description of mixed mode retention with the use of Box Cox transformation. Introduction of novel mixed mode retention parameters. Evaluation of turning point between hydrophilic and reversed phase interactions. Estimation of molecular properties governing the retention.
|
S0021967320301400
|
A solid phase microextraction coupled with flash evaporation gas chromatography method was applied to the determination of phthalate esters . Polysulfone hollow fiber at 1cm length was employed as extraction element to adsorb PAEs directly . Predominant parameters including stirring velocity salt concentration extraction time and extraction temperature were optimized . PSF fiber with absorbed PAEs was put into a small sample cup . The extracted analytes were thermally desorbed at 300C in a pyrolyzer and then entered into a column for separation . The linearity of the method was satisfactory over a concentration range of 21000g L with the correlation coefficients
|
Solid phase microextraction with polysulfone hollow fiber. Direct injection of hollow fiber was performed using a pyrolyzer. Determination of ten PAEs in ten real bottled water samples. This approach proved to be convenient and environmentally friendly.
|
S0021967320301412
|
RPLC MS MS is the present workhorse for bottom up proteomics based characterization . However it suffers from limited peak capacity and challenges with respect to detection of small and hydrophilic peptides . CZE MS MS offers an orthogonal alternative to RPLC MS MS but has limited sensitivity due to low sample loading . In the present work for the first time offline coupling of an RPLCCZEMS MS has been demonstrated for peptide mapping of a monoclonal antibody based therapeutic product . The performance of this platform has been compared to the state of the art RPLC MS MS and CZE MS MS approaches . Fifteen fractions were isolated from a mAb tryptic digest using RPLC and each fraction was analyzed by CZE ESI MS MS . Results indicate that not only the RPLCCZEMS MS platform identified a larger number of distinct peptides than the RPLC MS MS and CZE MS MS platforms it also offered significantly superior sequence coverage . Also the distribution of amino acid residues with post translational modifications was 413 for RPLCCZEMS MS 150 for RPLC MS MS and 94 for CZE MS MS . In fact the RPLCCZEMS MS system performed better than the combined datasets from RPLC MS MS or CZE MS MS. Our study shows that the traditionally used one dimensional RPLC MS MS and CZE MS MS based platforms may not be enough for characterization of complex molecules such as monoclonal antibodies . The proposed approach should be an essential addition to the analytical toolkit for in depth primary structural characterization of mAbs .
|
A RPLCCZE MS MS platform was used for the first in depth mAb characterization. RPLCCZEMS MS covered more sequence peptides PTMs than RPLC MS MS CZE MS MS. It was more informative than even the combined datasets of RPLC MS MS CZE MS MS. 1D RPLC and CZE methods are thus not enough for characterization of mAbs. RPLCCZEMS MS should be added to the analytical toolbox for mAb characterization.
|
S0021967320301424
|
The complexity of determining the composition of animal tissue lipids is greatly increased by the presence of plasmalogens in which the alkyl chain is linked to glycerol by an enol ether bond instead of being esterified . Acidic methanolysis of animal tissue lipids provides the simultaneous scission of acyl and alkenyl ether moieties but the complexity of the products of reaction poses a great challenge in their gas chromatographic analysis . Two dimensional gas chromatography with online reduction provided the resolution of all components contained in acid methanolyzed animal lipids taking advantage of the selective hydrogenation of alkenyl ether methanolysis products prior to the second dimension separation
|
We revisisted the preparation of dimethyl acetals from plasmalogens and made recommandations to avoid unwanted degradation products. Two dimensional gas chromatography with online reduction separates dimethyl acetals and fatty acid methyl esters. Dimethyl acetals prepared from plasmalogens may be isolated from fatty acid methyl esters by liquid liquid repartition. Results are confirmed by applying GC MS and NMR spectroscopy.
|
S0021967320301631
|
The suitability of supercritical fluid chromatography coupled to accurate mass spectrometry for the determination of seven commercial neonicotinoid pesticides and one transformation product in wine samples has been investigated . Thorough optimization of the different parameters affecting the SFC MS selectivity and sensitivity was carried out . Under final conditions a 2mL volume of either red or white wine was extracted by SPE and analysed using external standard calibration achieving limits of quantification from 1 to 11ng mL
|
SFC MS optimized parameters for neonicotinoid pesticides analysis. High extraction yields and low matrix effects for SPE wine extracts. Superior performance of SFC MS compared to UPLC MS. Imidacloprid residues often found in wine samples.
|
S0021967320301643
|
As a novelty the combination of headspace solid phase microextraction and gas chromatography coupled to an Orbitrap mass analyzer in full scan mode was evaluated for the monitoring of organic pollutants in wastewaters . The developed methodology showed good linearity R
|
A novel automated method for screening of organic pollutants was developed. The combination of HS SPME with GC Orbitrap MS has been proposed for first time. The developed method resulted robust reliable and highly sensitive and selective. Target post target and non target analysis of wastewaters detected 54 pollutants. The methodology is a breakthrough for the screening of pollutants in water samples.
|
S0021967320301667
|
Stationary phases with multiple mode mechanism are beneficial to meet the needs of complex samples but there are few multiple mode stationary phases which can adjust the relative strength among multiple forces imposed on the solutes . This work presents a facile preparation method of reverse phase hydrophilic interaction ion exchange tri mode stationary phase in which three functional monomers lauryl methacrylate hydroxyethyl methylacrylate and dimethylaminoethyl methacrylate as co monomers underwent surface initiated atom transfer radical polymerization on the surface of silica . The structure of stationary phases was characterized and their chromatographic properties were investigated using various solutes . By comparison with classical single mode columns it is found that the newly designed columns can offer multiple interactions including hydrophobic hydrophilic and electrostatic interactions and show good separation abilities to the tested solutes . Besides changing the ratios of LMA HEMA and DMAEMA in SI ATRP system can easily adjust the relative strength of three interactions imposed on the solutes inducing adjustable separation selectivity of the columns . The improved separation of multivitamin sample and the successful use of the columns in
|
RP HILIC IEC stationary phase was prepared by ATRP of mixed three monomers. The relative strength of three interactions is adjusted. the ratio of three monomers. Separation selectivity varies with ratios of three monomers. Stationary phases is successfully used in. aqueous liquid chromatography. The column shows the potential in the separation of multivitamin sample.
|
S0021967320301679
|
Human epidermal growth factor receptor 2 gene expresses a transmembrane glycoprotein that is over expressed in 1530 breast 3 lung and other several digestive cancers . So HER2 is a good biomarker for tumor diagnostic and treatment monitoring . Clinically detection of HER2 often employs invasive approaches with tissue samples which at large extent limit its universal application . Shedding of the extracellular domain of the HER2 into the circulation has led to the development of a serum test of HER2 ECD as an additional approach to probe the HER2 overexpression . However few methods were developed due to the high sensitivity required by the serum HER2 ECD determination . In this work we prepared a novel immunoaffinity in tube solid phase microextraction sorbent for selective enrichment of HER2 ECD . Two clinical available monoclonal antibodies against to HER2 trastuzumab and pertuzumab were selected as immunoaffinity ligands . Porous layer open tubular capillary with oriented antibody immobilization were fabricated and systematically optimized to afford a higher extraction capacity . The capacity was reached to 120.4g m which is more than 1000 times higher than that obtained by a common method . After sample extraction and enrichment by the IT SPME the eluent were determined by a particle enhanced turbidimetric immunoassay . Sensitive quantification of HER2 ECD by the PETIA was thereby accomplished . HER2 ECD concentrations in 82 clinical serum samples were determined by the developed IT SPME PETIA method and the results were well correlated with that by the clinical used chemiluminescence immunoassay . Besides the IT SPME PETIA method was found providing 5 times higher sensitivity than the CLIA and 500 times higher than the PETIA without IT SPME . The results indicate that the developed method is suitable for high sensitive quantification of HER2 ECD in clinical samples .
|
An immunoaffinity in tube SPME sorbent for selective enrichment of HER2 ECD was prepared. A PLOT capillary 250m ID 1m layer thickness and 8nm mesoporosity was used for the SPME. Sensitive quantification of serum HER2 ECD was accomplished.
|
S0021967320301680
|
A high sampling rate good stability high throughput masking fluorescence detection system with easy positioning of each channel for capillary array electrophoresis was prepared and studied . A special mask combined with convex lenses was designed to modulate signals without using any extra device to position each channel . The signal of each channel was detected by a photomultiplier tube classified and saved by software . The design was used to evidently reduce the rotational vibration of optical components and to stabilize the system so a high sampling rate was obtained by increasing the DC motor speed . To improve the optical system optical fibers instead of conventional bulky optical components were used to transmit optical signal and to collect fluorescences in multiple directions which greatly raised the sensitivity . Other important parameters including sampling rate rotating speed and driven voltage laser diode have also been investigated . Under optimal conditions the performance of the detection system was evaluated . This novel system had a well designed structure and allowed independent multiple capillary operations and easy microanalysis . Its limit of detection for rhodamine 6G was 2.010
|
A masking fluorescence sharing detection system for capillary array electrophoresis was established. A special mask combined with convex lenses was designed to modulate signals without using any extra device to position each channel. The detection cell was designed to not only decrease noise but also collect fluorescence in multiple directions. To meet the needs of different excitation wavelengths the system was adopted modular design which was conducted to facilitate installation and replacement. The system can be easily home built accompanied by high sensitivity as well as high throughput and precision.
|
S0021967320301692
|
Room temperature ionic liquids are well established stationary phases for gas chromatography in several fields of applications because of their unique and tunable selectivity low vapor pressure and volatility high thermal stability and good chromatographic properties . This study is focused on an IL based on a phosphonium derivative phosphonium chloride P
|
P. Cl. an ionic liquid GC stationary phase with peculiar selectivity. The maximum allowable operating temperature of P. Cl. IL is 210C. Development of a dedicated approach for analytes eluting above 210C. Tuning of column characteristics and operative conditions. P. Cl. selectivity compensate the loss of efficiency of short columns.
|
S0021967320301709
|
This study focuses on the health benefits of several fresh herbs that are commonly used in the Mediterranean diet . Antioxidant activity phytosterol content and amylase inhibitory activity of fresh basil lavender oregano rosemary sage and thyme are analyzed and compared . High performance thin layer chromatography combined with effect directed analysis was used to detect and quantify biological active compounds on chromatograms . The highest antioxidant activity was measured in the extract from oregano leaf while the highest terpenoid content was in basil leaf extract . All extracts except lavender leaf and lavender flower extracts showed amylase inhibition . The same compound at
|
Culinary herbs exhibit antioxidant activity amylase inhibition and provide neuroprotection. Pentacyclic triterpenes are amylase inhibitors with neuroprotective potential. HPTLC EDA combined with ATR FTIR enables bioassay guided identification of active compounds.
|
S0021967320301710
|
When cyclodextrins are used in chromatography analytes retention time is decreased with an increase in concentration of CD in the mobile phase . Thus complex stability constants can be determined from the change in retention time of the ligand molecule upon complexation . Since the preceding approach implies extensive and time consuming HPLC experiments the goal of this research was to investigate the possibility of using in silico prediction tools instead . Quantitative structureretention relationship model previously developed to explain the retention behavior of risperidone olanzapine and their structurally related impurities in CD modified HPLC system was applied to predict retention factor under different chromatographic conditions within the examined domains . Predicted retention factors were further used for calculation of stability constants and important thermodynamic parameters namely standard Gibbs free energy standard molar enthalpy and entropy contributing to inclusion phenomenon . Unexpected prolonged retention with an increase in CD concentration was observed in contrast to the employed chromatographic theory used for the calculation of the stability constants . Consequently it led to failure in stability constants and thermodynamic parameters calculation for almost all analytes when acetonitrile content was 20 across the investigated pH range . Moreover ionization of investigated analytes and free stationary phase silanol groups are pH dependent leading to minimization of secondary interactions if free silanol groups are non ionized at pH lower than 3 . In order to prove accuracy of predicted retention factors HPLC verification experiments were performed and good agreement between predicted and experimental values was obtained confirming the applicability of proposed in silico tool . However the obtained results opened some novel questions and revealed that chromatographic method is not overall applicable in calculation of stability constants and thermodynamic parameters indicating the complexity of CD modified systems .
|
Chromatographic approach in complex stability constant assessment is time consuming. QSRR model was used to predict change in analyte retention time upon complexation. Predicted change in retention time was used to calculate stability constants. HPLC and QSRR approach were not applicable under all experimental conditions. CD concentration and acetonitrile content affected stability constant calculation.
|
S0021967320301722
|
This paper reports for the first time the coupling of a two dimensional separation technique known as orthogonal pressurised planar electrochromatography with on line UV VIS detection . It establishes the efficiency characteristic of a planar column used in OPPEC . The studies show that in OPPEC all separation steps can run successfully as non separate operation much like in HPLC and the planar column has itself good efficiency ensuring a relatively low plate height value . In its use some findings of the previously proposed theoretical model concerning optimisation of preparative separation of components with the same electrophoretic mobility are verified showing that there is a good agreement between theory and experiment .
|
The entire OPPEC separation process can run in a fully online operating mode. There is good agreement between theory and experiment. OPPEC periodic mode separates substances with equal electrophoretic mobility. Successful micro preparative separation of a real post reaction mixture was conducted. Advantage of OPPEC vs HPLC for productivity and eluent consumption is possible.
|
S0021967320301734
|
Low levels of inorganic arsenic and As in fishery products have been selectively isolated from fish extracts by ionic imprinted polymer based solid phase extraction procedure . The selective adsorbent was synthesized using sodium arsenite as a template 1 vinyl imidazole as a functional monomer divinylbenzene as a cross linker and 2 2 azobisisobutyronitrile as an initiator . Optimized pre concentration conditions imply fish extract pH adjustment at 8.5 before loading flow rate of 0.25mL min
|
Selective determination of low concentrations of As III and As V in the presence of large concentrations of organoarsenic compounds. Speciation of low concentrations of inorganic arsenic in fishery products. Simple and low cost synthesis of ionic imprinted polymer for solid phase extraction.
|
S0021967320301758
|
Consumption of sports drinks is generally associated with a healthy lifestyle despites a common addition of colorants and preservatives to these products . This work presents the novel methods based on high performance liquid chromatography and capillary electrophoresis aimed at the simultaneous quantification of both these groups of additives within a single separation . The results obtained show that colorants are generally added in low and rather safe amounts whereas preservatives are much more abundant and likely pose a potential risk especially for children . The overall potential of the HPLC and CE methods was critically assessed and compared using the RGB additive color model a user friendly tool that allows one to point out and encode particular capabilities and general potential of a method using colors and to express its holistic effectiveness with one integrated quantitative parameter from 0 to 100 . As a result the potential predispositions of both methods were delineated .
|
Food preservatives and colorants quantified in sports drinks by CE and HPLC methods. Amounts of colorants are rather safe whereas preservatives potential dangerous. CE and HPLC were profoundly and transparently compared using the RGB color model. The choice of a better method depends on the weight of the green criteria.
|
S002196732030176X
|
This study proposed the developed of a molecularly imprinted polymer for the extraction and determination of condensed tannins from the barks of Red Angico
|
MIP was successfully used to concentrate tannins in natural sources. An effective methodology for tannins extraction has been developed. Molecularly imprinted polymers were evaluated as SPE extraction phase. MISPE was used for tannins concentration from Jabuticaba Umbu and Angico.
|
S0021967320301771
|
To explore the retention and separation of stevioside polar compounds on a sulfonic acid functionalized cation exchange column the effects of different organic solvent water mobile phases on the retention behavior of polar rebaudioside A and its analogues on the column were investigated over a wide range of organic solvent contents . The obtained U shape curves hinted that the retention of the compounds on the same column transitioned from a reversed phase liquid chromatography mode to a hydrophilic interaction liquid chromatography mode when the water rich state in the mobile phases changed to an organic solvent rich state . Under the RPLC mode no separation of RA from its analogues was observed . The HILIC mode was beneficial to the retention and separation of RA and its analogues . Compared with polar protic solvents aprotic solvents were more conducive to the retention and separation of the polar compounds based on the HILIC mode in organic solvent rich mobile phases . Three models were used to evaluate and discuss the HILIC retention and separation of the compounds on the column . In the aprotic solvent rich mobile phase the HILIC retention of RA and its analogues was effectively described by a mixed mode model in the polar proton solvent rich mobile phase the retention of analytes was best described by an linear solvation strength model . The content and composition of the organic solvent in the mobile phase were determined to be important influencing factors that regulated the retention time for the RA and its analogues and even the separation mechanism for HILIC . The present work provides a theoretical basis for guiding one to prepare high purity RA from its analogues by predicting the retention time .
|
The HILIC mode was beneficial to the retention and separation of RA and analogues. Aprotic solvent was more conducive to the separation of RA following the HILIC mode. Retention of RA in an aprotic rich system was best described by a mixed mode model. Retention of RA in a proton rich system was best described by an LSS model.
|
S0021967320301795
|
In general counter current chromatography systems there are several off column fittings between injector and column inlet such as bends valves connecting tubes and joints . Due to these off column fittings the sample will diffuse in the mobile phase and form an irregular distribution when it flows from the injector to the column inlet . Thus the concentration distribution of the solutes at the column inlet is a continuous curve . As some previous research reveals it is necessary to input actual injection profile into the simulation model to mimic elution profile . Therefore we built a non ideal CCC model whose initial value is from the actual injection profile and validated the rationality of this model with iteration method . The simulation analysis of different injection profiles shows the conditions whereby a discrete injection profile can replace the actual injection profile in the non ideal CCC model for accurate simulation elution . Simulation elution under such conditions reveal that non ideal injection model can reflect the relationship between the injection profile and elution profile and help to explain the reasons of irregular change in elution profile like the tailed peak and flat peak .
|
In this paper we built a non ideal injection model based on equilibrium cell model and validated its rationality using iteration method. The simulation analysis of different injection profiles shows the conditions whereby a discrete injection profile can replace the actual injection profile to mimic the elution process. The research reveals that non deal injection model can reflect the relationship between injection profile and elution profile and help to explain the causes of irregular changes in the elution profile.
|
S0021967320301813
|
Dynamic pressure gradient modulation is investigated for comprehensive two dimensional gas chromatography with time of flight mass spectrometry detection . With DPGM a commercial pneumatic pulse valve is opened to introduce a suitably high auxiliary gas pressure at a T junction connecting the first dimension
|
Low flow conditions are employed with flow modulation. Dynamic pressure gradient modulation in full modulation mode is utilized. Fully modulated peaks provide enhanced signal and low limit of detection. The evaluation of the quality of the data using chemometric tools is provided. Decomposition of poorly resolved analytes at low concentration was successful.
|
S0021967320301825
|
This work described the development of a novel method for simultaneous extraction of eight active compounds from Yaobitong capsule by accelerated solvent extraction . Response surface methodology with desirability functions was employed to optimize the extraction conditions yielding the optimal conditions of ASE . A high performance liquid chromatography coupled with a diode array detector method was developed and validated for simultaneous quantification of the eight compounds in Yaobitong capsule . The values of correlation coefficient were satisfactory between 0.9992 and 0.9999 over the linear concentration range of 0.51000g mL
|
An ASE method for extraction active ingredients in Yaobitong capsule was developed. Box Behnken design was used to optimize the extraction conditions. A HPLC DAD method to quantify eight compounds from Yaobitong capsule was proposed.
|
S0021967320301849
|
Human plasminogen Kringle 5 is known to pose a more potent anti angiogenesis effect by inducing endothelial cell apoptosis . Our previous studies have identified the peptide IGNSNTL as a binding sequence of Kringle 5 using Ph.D. 7 phage display peptide library and enzyme linked immunosorbent assay . Here eleven proteins were screened and summarized by BLAST laminin 3 chain G1 domain was considered as the most potential receptor based on E value and domain function . The specific interaction of them was directly revealed through ligand blot and a strong concentration dependent manner occurred between them K
|
Human laminin 3 chain G1 domain is a binding receptor of plasminogen Kringle 5 in vitro. A rapid screening and validation strategy of researching receptor was established. Electrostatic force and hydrogen bond are the driving forces for interaction. Conformational change among random coils and helixes are observed for LG1 domain.
|
S0021967320301850
|
It is critical to determine the chiral impurity profile of pharmaceutical compounds . The rising trend of drug candidates bearing multiple chiral centers has aggravated the analytical challenges . The traditional chiral HPLC methods can take gruelingly long time to develop yet may not offer sufficient resolution for all stereoisomers . A fast analytical strategy with a high success rate is in urgent demand for compounds with multiple chiral centers . In this study we have developed an effective and fast multiple heart cutting multicolumn two dimensional liquid chromatography LC
|
A multiple heart cutting multiple columns. LC. LC strategy was developed. Separate isomers of compounds with multiple chiral centers and achiral impurities. Simplify multiple chiral center separation into single chiral center separations. Dramatically reduces chiral method development time and sample analysis turnaround. Demonstrated by two case studies of complex pharmaceutical samples
|
S0021967320301862
|
Traditional Chinese medicine especially herbal medicine compound preparation faces great challenges in its quality control due to a myriad of components involved . How to perform quality control of TCM more effectively has been a research topic . In this study we used Tianmeng oral liquid as a case study and developed a comprehensive strategy based on non targeted targeted and bioactive analyses for quality evaluation of TOL from different batches . Firstly a non targeted fingerprinting analysis was performed by HPLC DAD and UHPLC MS MS. Twenty five batches of TOL were clearly discriminated by similarity analysis and hierarchical cluster analysis and components were tentatively identified . Secondly the targeted quantitative methods based on HPLC DAD and HPLC MS were applied to simultaneous quantitative determination of five and eight marker compounds especially toxic component strychnine respectively . The quantitative data were processed with principal component analysis for differentiating different batches of samples . Finally we explored the feasibility of establishing a total antioxidant capacity model . How to use the peak area instead of the corresponding concentration to determine the antioxidant activity related compounds was theoretically explained for the first time which was of great significance for the study of the fingerprint efficacy relationship . The orthogonal signal correction partial least squares model was employed to predict the TAC of TOL from their chromatographic fingerprints and identify three potential antioxidant markers . These results demonstrated that the comprehensive strategy from fingerprinting chemical composition multiple component quantification and antioxidant activity could be applied to quality evaluation of TOL and discrimination of the expired and unexpired samples .
|
Propose a strategy based on non targeted targeted and bioactive analyses. Theoretical explanation provided for determining activity related components. Total antioxidant capacity model was successfully developed. The model was used to predict antioxidant capacity and identify antioxidant marker.
|
S0021967320301874
|
A GCMS based analytical method was developed for the profiling of oil based AAS products using 15 organic constituents as target compounds . A total of 219 compounds were identified in 109 seized AAS products among them 15 target compounds were selected . The selection was based on each compound s occurrence reproducibility and variance between products . The 15 target compounds did not include the active steroid itself but only compounds found in the carrier oil . The subsequent method validation included assessment of specificity linearity precision robustness and sample stability . The method was finally applied for the classification of a set of 27 seizures of AAS products supplied by the police . The classification was based on the Pearson correlation coefficient using pre treated peak area data from the 15 target compounds . A successful classification was obtained with only a small overlap between linked and unlinked samples . A 1 false positive rate could be obtained at a threshold of 0.625 in terms of the Pearson distance . The present study thus demonstrates that it is possible to profile and classify AAS products with regard to a common origin . As the profiling method is not specific with regards to the steroid content it may potentially be used to profile and compare other kinds of oil based liquids .
|
A GCMS based method including derivatization was developed and validated. 15 target compounds originating from the carrier oil of AAS were selected for profiling. 109 AAS products from 44 seizures were included in the method development. Classification of AAS specimens using the Pearson correlation coefficient was performed.
|
S0021967320301886
|
To reach a high separation efficiency using Centrifugal Partition Chromatography the fluid dynamical behavior of the liquid liquid two phase systems must be clearly understood . The fluid dynamics namely the dispersion the coalescence and the stationary phase retention have a high impact on a separation . Especially the mobile phase dispersion influences the mass transfer during a separation . In this study the mobile phase dispersion of different aqueous organic solvent systems was characterized for ascending and descending mode via video analysis . Thereby the influence of the physical properties of the solvent systems the operating parameters and the geometry of the chamber inlet was investigated systematically using dimensional analysis . With the help of the dimensionless numbers Ohnesorge number Oh
|
Optical determination of mobile phase dispersion in Centrifugal Partition Chromatography. Categorization of different states of dispersion. Systematic approach analyzing the influences on the dispersion. Correlation with Ohnesorge number Weber number and Etvs number describing dependency of the dispersion. Correlation in accordance with influences described in literature.
|
S0021967320301898
|
We present relationships between the multiscale structure and the separation properties of size exclusion chromatography columns . Physical bed reconstructions of wall and bulk regions from a 2.1mm i.d . column packed with fully porous 1.7m bridged ethyl hybrid particles obtained by focused ion beam scanning electron microscopy serve as geometrical models for the packing microstructure in wall and central regions of a typical narrow bore SEC column . In addition the intraparticle mesopore space morphology of the BEH particles is reconstructed using electron tomography to ultimately construct a realistic multiscale model of the bed morphology from mesopore level via interparticle macropore space to transcolumn scale . Complemented by the results of eddy dispersion simulations in computer generated bulk packings relationships between packing microstructure and transchannel short range interchannel as well as transcolumn eddy dispersion are used to analyze the fluid dynamics in the interparticle macropore space of the model . Further we simulate hindered diffusion and accessible porosity for passive finite size tracers in the intraparticle mesopore space to finally determine the effective particle and bed diffusion coefficients of these tracers in the hierarchical bed . Retention and transport properties of polystyrene standards with hydrodynamic diameters from 5 to 95 in tetrahydrofuran are subsequently predicted without introducing bias from arbitrary models . These properties include the elution volumes of the polystyrene standards the global peak capacity and the rate of peak capacity at any fixed elution volume . Optimal flow rates yielding maximal global peak capacity and a nearly uniform rate of peak capacity over the entire separation window are close to 0.04 and 0.20mL min respectively . SEC column performance obtained for fully porous and superficially porous particles is compared by varying the core to particle diameter ratio
|
Morphology transport relationships in liquid chromatography are investigated. Bed microstructure and intraparticle mesopore space morphology are reconstructed. FIB SEM and electron tomography are used to derive realistic geometrical models. Bed and intraparticle diffusion coefficients are directly simulated in these models. Application is made to differently sized analytes and method development in SEC.
|
S0021967320302053
|
Gas chromatography mass spectrometry is a robust analytical platform for analysis of small molecules . Recently it is widely used for large scale metabolomics studies in which hundreds or even thousands of samples are analyzed simultaneously producing a very large and complex GC MS datasets . A number of software are currently available for processing GC MS data but it is too compute intensive for them to efficiently and accurately align chromatographic peaks from thousands of samples . Here we report a newly developed software QPMASS for analysis of large scale GC MS data . The parallel computing with an advanced dynamic programming approach is implemented in QPMASS to align peaks from multiple samples based on retention time and mass spectra enabling fast processing large scale datasets . Furthermore the missing value filtering and backfilling are introduced into the program greatly reducing false positive and false negative errors to be less than 5 . We demonstrated that it took only 8h to align and quantify a GC TOF MS dataset from 300 rice leaves samples and 17h to process a GC qMS dataset from 1000 rice seed samples by using a personal computer . QPMASS is written in C programming language and is able to run under Windows operation system with a user friendly interface .
|
QPMASS is developed for quickly processing large scale GC MS data. It can achieve accurate peak alignment results with low misalignment rate . It has high accuracy in peak quantification. It runs under commonly used Windows system.
|
S0021967320302065
|
This work focused on the development and validation of a method based on hollow fiber based solid phase microextraction coupled to ultra performance liquid chromatography tandem mass spectrometry for the determination of five antipsychotics at a pg mL
|
Polyether sulfone hollow fiber without any modification is selected as adsorbent for sample preparation. Due to porosity of hollow fiber high adsorption capacity can be achieved. This method exhibits excellent sensitivity pg mL. .
|
S0021967320302077
|
Mass spectrum is one of the most commonly used tools for qualitative and quantitative analysis of glycans . However due to the complexity of biological samples and the low ionization efficiency of glycans these need to be purified and derivatized prior to MS analysis . Existing purification strategies require a combination of multiple methods and are cumbersome to operate . Here we propose a new method for the purification of glycoprotein N O glycans and their derivatives using a hand packed absorbent cotton hydrophilic interaction chromatography column . The method s reliability and applicability were verified by purifying N O glycans and the derivatives of standard glycoproteins such as chicken albumin and porcine stomach mucin . Stable isotope labelling was used to compare the glycans recovery following different purification methods . Absorbent cotton HILIC was also successfully applied for the analysis of human serum and fetal bovine serum glycoprotein N glycans . Finally testing revealed high binding capacity 9mg g
|
We propose a new absorbent cotton hydrophilic interaction chromatographic column HILIC for N and O glycans and their derivatives purification. The new method is suitable for chemically or enzymatically released glycans. The method allows for a better recovery of N glycans than solid phase extraction SPE columns. The method can be used for the purification of O glycans released by. elimination. The method can successfully detect glycans in complex biological samples.
|
S0021967320302090
|
The enormous growth in drug discovery paradigm has necessitated continuous exploration of new methods for drug protein interaction analysis . To enhance the role of these methodologies in designing rational drugs this work extended an immobilized angiotensin II type I receptor AT
|
Immobilized AT. R chromatography was prepared by a one step method. Thermodynamic and kinetic parameters of four ARBs have been measured by injection amount dependent method and peak profiling method. The hit identification of puerarin and rosmarinic acid has been evaluated by the immobilized AT. R chromatography.
|
S0021967320302107
|
In the present study a fast multiresidue method determining three novel fungicides fenpicoxamid isofetamid and mandestrobin in cereals was developed and validated for the first time using ultrahigh performance liquid chromatography coupled to tandem mass spectrometry . Samples were extracted by QuEChERS methodology and cleaned up using the disposable pipette extraction tips containing primary secondary amine and silica gel modified with zirconium oxide in less than 1min . Linearity
|
Determination of novel fungicides fenpicoxamid isofetamid and mandestrobin in cereals for the first time. First analytical report on fenpicoxamid and mandestrobin. Sample clean up by disposable pipette extraction DPX tips took less than a minute. DPX tips containing PSA and Z Sep removed the most co extractives and provided good analyte recoveries.
|
S0021967320302119
|
The prediction of the performance of a Centrifugal Partition Chromatography is a difficult but desirable task . The partitioning of the sample as well as the fluid dynamical phenomena dispersion coalescence and stationary phase retention have to be individually understood . Therefore the phase settling behavior of different aqueous organic solvent systems and with this the dependency of the stationary phase retention in CPC was investigated in this study . On the one hand batch settling experiments were performed and the settling velocity of aqueous organic solvent systems was investigated . With this it was possible to correlate the stationary phase retention in CPC in both operating modes . For descending mode operation a high settling velocity of the lower phase and for ascending mode a high settling velocity of the upper phase is needed for a stable operation and a high stationary phase retention .
|
Settling velocity and stationary phase retention of aqueous organic solvent systems. Determination of phase inversion point of a dispersion in settling experiments. Correlating settling velocity and stationary phase retention in CPC. Description of all interactions using the Capillary number and the Morton number. Correlations in accordance with influences described in literature.
|
S0021967320302120
|
This paper reports an optimized multiresidue extraction strategy based on the Quick Easy Cheap Effective Rugged and Safe extraction procedure and on solid phase microextraction for the simultaneous screening of 120 pesticides 16 polycyclic aromatic hydrocarbons and 22 polychlorinated biphenyls from the terrestrial snail
|
QUECHERS SPME for the quantification of pesticides PAHs and PCBs in snails samples. Comparison of ASE and QUECHERs for snails analysis. Comparison of acetonitrile and ethyl acetate as solvent extraction for QuEChERS extraction. Application on the use of snails as environmental biomonitors.
|
S0021967320302132
|
Evaluation of chiral pesticides remains a frequently neglected matter in routine food control laboratories . This fact is due to the existence of many residue definitions but also due to the lack of robust instrumental methods for the evaluation of these isomeric compounds . However supercritical fluid chromatography coupled to mass spectrometry has been demonstrated to perform fast and highly efficient separations without the need to change the mobile phase employed in multiresidue pesticide analyses . Regarding chiral stationary phase columns the polysaccharide based ones clearly demonstrate the best separation technology . Two polysaccharide based columns were tested in this study and the robustness of their combination with SFC was verified . The enantiomers of lambda cyhalothrin and metalaxyl were studied precisely due to their markedly distinct toxicity and enantioselectivity . Furthermore the acute reference dose for gamma cyhalothrin is half in comparison with its enantiomer which is present in the lambda cyhalothin residue definition . These enantiomers were analyzed in terms of linearity reproducibility and matrix effects in four representative matrices . Additionally field tests under greenhouse conditions for these compounds were performed . The results obtained after different sample collections revealed a similar degradation in lambda cyhalothrin enantiomers but not in the case of metalaxyl M where the degradation in tomato was 2 to 6 times less in comparison with its S enantiomer .
|
Enantioseparation of 21 chiral pesticides using supercritical fluid chromatography. Testing two polysaccharide based columns to perform the chiral separations. Study of two enantioselective isomers Metalaxyl and lambda Cyhalothrin. Evaluation of linearity reproducibility and matrix effect in four matrices. Performance of a greenhouse test to study the degradation of each enantiomer.
|
S0021967320302144
|
Table olives a widely consumed delicacy are often selected by consumers based on the shade of their green color . The appealing coloration of fresh olives fades to brown or pale yellow during the industrial processing necessary for commercialization and storage as a result of the degradation of chlorophyll a and b to their corresponding pheophytins and other chlorophyll degradation products . The re greening of table olives may be achieved by complexation of CDP with Cu
|
UHPLC ICP ID MS was first used to measure copper chlorophylls. Most chlorophylls in bright green table olives were complexed with copper. Bright green table olives contained total elemental copper above natural abundance. ICP ID MS provides quantitation of copper chlorophylls without using reference materials. High total elemental copper and copper chlorophyll content may be achieved by addition of copper salts.
|
S0021967320302156
|
A fast method for analysis of 47 pharmaceuticals active compounds in fish muscle has been developed and validated addressing the parameters accuracy precision matrix effect at three spiking levels 5 25 and 50ng PhACg
|
A miniaturized method was validated for the analysis of 47 drugs in fish muscle. Developed method a fast ultrasound USE extraction and Z Sep C18 sorbent clean up. HPLCQToF MS data adquisition with recording SWATH mode. Most frequently detected drugs caffeine carbamazepine diltiazem and verapamil. Suspect screening retrieved benzoylecgonine cocaine nicotine and ofloxacin.
|
S0021967320302168
|
In this paper adsorption mechanism of triterpenoid saponins in reversed phase liquid chromatography and hydrophilic interaction liquid chromatography was proposed based on the study of the retention behavior of mogroside V as test substance . The change of peak shape of mogroside V and its influencing factors was first investigated . As the increase of sample loading a tailing peak of mogroside V was observed in MeOH
|
Study of retention behavior and adsorption model of mogroside V in RPLC and HILIC. Strong dependency of peak shape of mogroside V from ACN ratio and temperature in RP. Langmuir model to describe adsorption of mogroside V in MeOH. O of RPLC and HILIC. Moreau or BET models simulated adsorption of mogroside V in ACN. O of RPLC or HILIC. Three methods for purification of mogroside V 98 from. extract.
|
S002196732030217X
|
Liquid liquid partition chromatography has been used for many years as a model and teaching introduction to column chromatography . However the partition model does not describe separations on bonded phases with porous supports particularly well especially regarding the thermodynamics controlling solute distribution . Further difficulties arise when more than one mechanism is involved in solute retention . Nomenclature is not perfectly aligned with the underlying thermodynamic descriptors and is inconsistently applied over various chromatographic techniques . Presented here is a general description of retention that spans partition size exclusion and hydrodynamic separation processes and is then applied to bonded phase separations on porous supports . The model provides a general description applicable to adsorption reversed phase hydrophilic interaction size exclusion hydrodynamic chromatography and any combination of these techniques including liquid chromatography at the critical condition . Further expansion to include retention by ion exchange and field flow fractionation appears to be possible . Recommendations on retention factor definition and evaluation are given .
|
A general retention model spanning multiple techniques is derived. Retention and thermodynamics are aligned and rationalized. Retention mechanisms are accounted individually or in combination. Retention factor is defined uniformly for all chromatography techniques.
|
S0021967320302181
|
Quantification of analysis results for the suspect and non targeted screening is essential for obtaining meaningful insight from the measurements . Ionization efficiency predictions is a possible approach to enable quantitation without standard substances . This is however especially challenging for the analysis carried out by combining the full scan mode either with fragmentation experiments in data dependent or data independent acquisition mode .
|
Standard free quantitation is possible via previously measured ionization efficiencies. Measured ionization efficiency values could be transferred to targeted screening. Fragmentation patters for different derivatization reagents are presented.
|
S0021967320302193
|
Dummy molecularly imprinted microspheres were synthesized by Pickering emulsion polymerization and used as the matrix solid phase dispersion extraction sorbent for sample pre treatment of azole fungicides in fish samples . Alpha 1H imidazole 1 ethanol was used as the fragment dummy template for the imprinting of climbazole clotrimazole and miconazole . The morphology of the microspheres were characterized by scanning electron microscopy and nitrogen adsorption measurements narrow diameter distribution with regular spherical shape and high surface area
|
Preparation and evaluation of DMIM for azole fungicides. DMI MSPD of CBZ CMZ and MNZ from fish samples using DMIM as the sorbent. Good recovery and reproducibility of the developed DMI MSPD HPLC method.
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.