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S0021961420301294 | Liquid liquid equilibrium data for water furfuryl alcohol solvent ternary systems were determined at | The LLE data for water TFP DIPE MTBE CH. Cl. MIBC were measured. The distribution coefficient and selectivity were calculated. The reliability of LLE data were verified by the Othmer Tobias Bachman and Hand equations. The NRTL and UNIQUAC models were applied to correlate the experimental LLE data. The binary interaction parameter values were obtained from the data correlation. |
S0021961420301415 | Densities and viscosities of ternary system and three corresponding binary systems and were determined at 7 temperatures from 293.15K to 323.15K . For the ternary system and binary systems the excess molar volumes | Density and viscosity of ethylcyclohexane 1 butanol ethyl caprylate mixtureswere investigated. Excess molar volumes and viscosity deviationwere calculated and correlated. The change of. and. is mainly due to the change of hydrogen bond and molecular structures. |
S0021961420301440 | Although salt ions severely distort the gas hydrate lattice this phenomenon is poorly realized in the existing statistical thermodynamics models . We propose a mechanistic model by addressing a novel concept of instability in the hydrate water film arising due to salt exclusion . The consequent water reorientation in the unstable lattice due to excluded ions is described in terms of the stress buildup in the hydrate lattice using Poiriers theory of crystal creep . Tolmans theory is reworked to account for the combined influence of guest and salt concentration on the surface energy of the phases in contact . Together with an empirical conformational term the three phase hydrate equilibrium is modelled . To describe the liquid phase non ideality the UNIQUAC and Pitzer activity coefficient models are combined . For vapour phase Patel and Teja equation of state is used whereas for hydrate phase Klauda and Sandler model is utilized . The particle swarm optimization is hybridized with simplex search algorithm to identify the model parameters . The proposed thermo physical hydrate model exhibits an improved performance over the existing models which is quantified in terms of absolute average relative deviation with respect to the experimental data . | Hydrate vaporliquid phase equilibrium model developed for electrolyte system. Modifications proposed in existing model of Klauda and Sandler. Effect of thermo physical properties on hydrate lattice structure considered. Latest thermodynamic models compared with respect to experimental data. |
S0021961420301506 | Extractive distillation with propyl propionate butyl propionate and butyl butyrate as extractive solvents is adopted to separate the binary azeotrope isopropyl alcohol isopropyl acetate . Through the relative volatility and | The entrainers were explored by relative volatility and. diagram. Propyl propionate butyl propionate and butyl butyrate were selected as entrainers. The VLE data for the systems isopropyl acetate entrainers were measured. The measured VLE data were correlated by the NRTL UNIQUAC and Wilson models. |
S0021961420301531 | The equilibrium solubility is the basis for purification and further theoretical studies of o vanillin . In this paper the solubility data of o vanillin in three pure solvents including water ethanol n propanol and two binary solvents of water ethanol and water n propanol has been experimented under atmospheric pressure | An isothermal saturation method was used to test the solubility of o vanillin. Modified Apelblat equation was used to correlate the experimental solubility data. The thermodynamic parameters such as. were achieved by vant Hoff analysis. Co solvency and liquid liquid phase separation phenomena was observed. |
S0021961420301592 | The saturated solubility of 6 phenyl 3 pyridazinone in aqueous co solvent mixtures of methanol ethanol isopropanol and ethylene glycol was determined through experiment by employing the saturation shake flask method at temperatures from 278.15 to 318.15K and local atmospheric pressure . For all the co solvent mixtures the maximum value of solubility was observed in neat methanol . The 6 phenyl 3 pyridazinone solubility in mole fraction scale was well correlated by using the Jouyban Acree model and vant Hoff Jouyban Acree model obtaining the values of relative average deviations smaller than 3.98 and root mean square deviation lower than 7.8110 | 6 Phenyl 3 2H pyridazinone solubility in four aqueous co solvent mixtures of alcohols was determined and correlated. Preferential solvation of 6 phenyl 3 2H pyridazinone in four mixtures was studied via IKBI technique. Solvent effect was studied in terms of solute solvent and solvent solvent interactions. |
S0021961420301725 | The viscosity of four dilution solution systems was determined for ionic liquids with Dimethyl Carbonate at lower concentration from 288.15K to 313.15K . The ILs include 1 ethyl 3 methylimidazolium bissulfonyl imide C | The four dilution of ILs C. mim NTf. C. mmim NTf. C. mim NTf. C. mmim NTf. with DMC were prepared. The viscosities of the systems have been measured and discussed. The relative viscosity have also been calculated and discussed. Influences of CH. and CH. CH. group introduction on properties were discussed. |
S0021961420301737 | D limonene is a monoterpene naturally found in citrus peels especially lemons and oranges and is responsible for their strong odour . D Limonene has specific properties that enable its use in various industrial segments such as foods perfumes beverages cosmetics pharmaceuticals detergents soaps insecticides disinfectants fine chemicals as a biodegradable solvent and so on . Among the ways in which limonene can be used the mixture of d limonene with alcohol compounds has a great application potential since alcoholic extracts of citrus essential oils have high solubility in aqueous solutions reducing the occurrence of oxidation reactions as well as increasing the aromatic resistance of the mixture . However studies on the thermodynamic properties of alcohol compounds and terpenes mixtures are still scarce . Thus in this study the density and excess molar volume data | Excess molar volume of d limonene alcohol compounds were all positives. Flash Point of d limonene alcohol compounds were highly non ideal. UNIFAC provided a better description of the Flash Point behavior than Ideal model |
S0021961420302044 | As one of the new generations of alternative refrigerants in the future hydrofluoroolefins and mixed refrigerants containing HFOs have gradually attracted attention . In this study the vapour liquid equilibrium for the binary system of isobutane 3 3 3 trifluoropropene was measured with a recirculation method at five temperatures of K. The uncertainties of the temperatures pressures and compositions are estimated to be less than 5mK 800Pa 0.005 respectively . The Peng Robinson equations of state with the Huron Vidal mixing rule involving the non random two liquid activity coefficient model were employed to correlate all the experimental data which had good fitting results . The maximum average absolute relative deviation of pressure AARD | The vapor liquid equilibrium VLE data for R600a R1243zf were measured. VLE data were correlated by Peng Robinson equation with Huron Vidal mixing rule. Azeotropic behaviours were found at a high mole fraction of R1243zf. |
S0021961420302135 | Using the saturation shake flask technique the equilibrium solubility of risperidone in co solvent mixtures of methanol water ethanol water isopropanol water and | Risperidone I solubility in four aqueous alcohol mixtures was determined. Solubility data were correlated by vant Hoff Jouyban Acree and Jouyban Acree models. Preferential solvation of risperidone I in alcohol solutions were derived via IKBIs method. Solvent effect was studied by using KAT LSER model. Cavity formation energy and dipolarity polarizability of solvents mainly controlled risperidone solubility. |
S0021961420302202 | In this study the solubility of musk xylene in four binary solvents was measured by the isothermal saturation method at temperatures ranging from 278.15K to 313.15K under atmospheric pressure . The results indicate that the solubility of musk xylene increases with increasing temperature and ethyl acetate mass fraction . The experimental solubility data of musk xylene were correlated by five thermodynamic models including modified Apelbla equation h equation Van t Hoff equation Sun model and JouybanAcree model . All models can be well correlated with the experimental data of solubility . The JouybanAcree model provides the best correlation in this study . The thermodynamic properties of the standard dissolution enthalpy | The solubility of musk xylene in binary solvents. Analysis of musk xylene by DSC and XRD. Five thermodynamic models were used to correlate the solubility date. The thermodynamic properties were calculated by the vant Hoff equation. |
S0021961420302317 | Crystallization and purification is an important step in drug preparation . In this work the solubility of doxofylline in some pure and mixed solvents at | The solubility of doxofylline in pure and binary solvents. The solubility data were correlated by some thermodynamic models. The effect of solvent properties on the solubility was analysed. Some thermodynamic properties of dissolution process were evaluated. |
S0021961420302342 | Thermodynamic data are the basis for design of crystallization process and control of crystal morphology and polymorph . In this work solubility data of L carnosine in different binary solvent mixtures including water were determined in temperatures ranging from 288.05K to 323.15K by static method under atmospheric pressure . It was found that the solubility data of L carnosine decrease apparently with the increasing of the mole fraction of organic solvent in binary solvent mixtures and increase with the rising of temperature . In addition the experimental solubility data were correlated and analyzed by the modified Apelblat equation the NRTL model and the JouybanAcree model to extend the applicability of the solubility data . Finally the standard dissolution thermodynamic properties including Gibbs energy entropy and enthalpy were calculated and discussed based on the experimental solubility data and Vant Hoff equation . | Solubility of L carnosine in three kinds of binary solvent mixtures were determined using gravimetric method. The experimental solubility data of L carnosine were correlated and analyzed by three thermodynamic models. Dissolution thermodynamic properties of L carnosine were calculated and discussed. |
S002196142030241X | The thermodynamic properties and phase behaviour of 1 3 diisopropylnaphthalene were studied for the first time using static vapour pressure measurements Tian Calvet calorimetry and differential scanning calorimetry . Polymorphic behaviour of the compound was detected and studied in detail by combination of DSC and variable temperature X ray powder diffraction . The crystal structure of the disordered metastable phase was obtained using a single crystal X ray diffraction for the first time . The experimental study was supplemented by calculating thermodynamic properties in the ideal gas state using a combination of statistical thermodynamics and quantum chemical calculations . Recommended vapour pressure equation was derived by simultaneous treatment of vapour pressures experimental heat capacities of the condensed phases calculated ideal gas heat capacities and temperature and enthalpy of fusion assuring their mutual thermodynamic consistency . | Thermodynamic and structural properties of 1 3 diisopropylnaphthalene were studied. New metastable disordered phase was detected and described. Consistent thermodynamic description was developed. |
S0021961420302792 | Micellisation of a binary mixture of sodium deoxycholate and sodium cholate is examined for the aqueous solution without additives and for the aqueous solution containing methanol NaCl and methanol NaCl in the temperature range | In the temperature interval. 278.15298.15 for micelle SD SC in the aqueous solution synergistic interactions exist. The impact of methanol from aqueous solution is expressed differently over. and. The effect of Na. ion is similar for both thermodynamic functions. and. Thermodynamic stabilization of mixed micelle SD SC is the highest if aqueous solution contains methanol and Na. ions as well. Novel thermodynamic functions are introduced for the thermodynamic stabilization of the binary mixed micelles. |
S0021961420303013 | Experimental data and modelling of electrolyte solutions are important in different fields . Separation and purification of such materials depend on knowledge of solid liquid equilibrium as well as the mathematical models allow the development of solution theories and process simulators . Therefore the current work presents the study of NaCl KCl and NH | Solubility of NaCl KCl and NH. Cl in mixtures of water and methanol was determined. The experimental data was correlated by the modified Pitzer model. |
S0021961420303220 | Nanometer copper possesses a broad range of applications in catalytic electrochemistry and functional materials and these applications are intimately associated with the thermodynamic properties of melting . In this paper we deduced the exact relationships between the integral melting enthalpy the entropy of the nanoparticles respectively particle size and discussed the influencing factors influencing regularities and influencing a degree on the thermodynamic properties of melting . Experimentally different sizes of Cu nanoparticles were prepared by the microwave method the melting temperatures melting enthalpies and melting entropies were determined by differential scanning calorimetry . The results demonstrate that the integral thermodynamic properties of Cu nanoparticles decrease with the reduction of particle size and vary linearly with the reverse particle size within the experimental size range . The experimental results are coherent with the theoretical predictions . | The integral melting enthalpy and the entropy of nanoparticle. The influencing of the thermodynamic properties of the melt. The changes in the thermodynamic properties of nanoparticles with particle size. |
S0021961420303347 | The limited availability of accurate experimental data in wide ranges of pressure temperature and composition is the main constraining factor for the proper development and assessment of thermodynamic models and equations of state . In the particular case of carbon capture and storage processes there is a clear need for data sets related to the mixtures that this work aims to address . This work provides new experimental | Design and operation of CCS processes need reliable thermodynamic models. New high precision experimental density data for CO. O. mixtures are reported. Thermodynamic models used in CCS processes are tested against high precision experimental data. Experimental data will foster the fundamentals of reference equations of state. |
S002196142030344X | In carbon capture utilization and storage a thorough understanding of thermophysical behaviour of the candidate fluid is an essential requirement for accurate design and optimised operation of the processes . In this communication vapour liquid equilibrium data of the binary mixtures of CO CO | VLE data for CO. CO at 253 to 298K. Results compared to the PR classical and WS mixing rules EoS GC and GERG EoSs. EoS GC with the specific departure function is superior to other models. |
S0021961420303566 | The liquid liquid equilibria data for the system were measured at 303.2K and 323.2K under 101.3kPa . The tie line data for both systems are displayed in the phase diagram with typical type I behaviour . The distribution coefficient and separation factor were calculated according to the measured tie line data . The calculated results suggest that both the two solvents can separate the diisopropyl ether and isopropyl alcohol mixture . Ethylene glycol possesses much better separation efficiency for low concentration extraction . The non random two liquids and universal quasi chemical models were applied to obtain the binary interaction parameters of pure components with all the root mean square deviation values less than 1.0 indicating the deviation of regression process can be acceptable . Based on Gibbs stability criteria the topological analysis with a graphical user interface confirmed the binary interaction parameters from data regression were well consistent with the experimental tie line data . | The LLE data for DIPE IPA PDO or EG were obtained at 303.2 K and 323.2K. PDO or EG as a solvent can efficiently separate IPA from DIPE mixture. NRTL and UNIQUAC models were used to correlate to the LLE data. The consistency of data regression were checked by the GUI MATLAB method. |
S002196142030358X | This contribution reported the equilibrium solubility of aprepitant in four binary aqueous mixtures of methanol ethanol acetone and 1 4 dioxane acquired through a shake flask method from 283.15K to 323.15K under local atmospheric pressure of 101.2kPa . At the same mass fraction compositions of methanol ethanol acetone 1 4 dioxane and temperature the mole fraction solubility of aprepitant was greater in mixture than in ethanol acetone methanol | Solubility of aprepitant form I in four aqueous mixtures was determined and correlated. Preferential solvation of aprepitant form I were derived via IKBIs method applied to solubility. Solvent effect on solubility variation was investigated through KAT LSER model. |
S002196142030361X | The aim of this paper is to enhance the knowledge on the behaviour and thermodynamic properties of natural and synthetic biopolymers in aqueous solutions . The acid base properties of Carrageenan | The study improves the knowledge on the behaviour and thermodynamic properties of some biopolymers. The variation of the constants in dependence on ionic strength has been modelled. The binding ability of the polymers has been investigated towards Ca. Zn. and Sn. The effect on the complexing ability of a secondary inorganic ligand has been evaluated. The sequestering ability of the polymers towards the metal cations has been evaluated by the pL |
S0021961420303645 | In this work isothermal vapour liquid equilibrium data for the binary mixtures of pentafluoroethane 2 3 3 3 tetrafluoroprop 1 ene and trans 1 3 3 3 tetrafluoropene have been investigated . The experimental measurements were carried out by using the | The. analytical apparatus was applied to carry out the measurements. The VLE data for the two binary systems R125 R1234yf and R125 R1234ze E were measured at five temperatures. The experimental VLE data were correlated by the PR type WS NTRL models. The systems exhibited zeotropic behavior at the studied temperatures. |
S0021961420303694 | Equilibrium apixaban solubility in isopropanol water ethanol water acetone water and methanol water mixtures was acquired by a shake flask method from 288.15K to 328.15K under atmospheric pressure of 101.2kPa . At a certain temperature the highest apixaban solubility in mole fraction scale was observed in neat solvents of acetone methanol for the acetone methanol water solutions while for the ethanol isopropanol water solutions the solubility data presented a maximum value with the ethanol isopropanol mass fraction of about 0.8 . The determined solubility values were treated by linear solvation energy relationships in order to explain the solvent effect and find its major descriptors . The preferential solvation was studied by the method of inverse KirkwoodBuff integrals based on some thermodynamic solution properties . In the methanol water mixture with compositions 0.31 | Apixaban I solubility in four aqueous co solvent mixtures was determined. Solubility data was correlated Jouyban Acree and vant Hoff Jouyban Acree models. Preferential solvation of apixaban I in four mixtures was studied via IKBI technique. Solvent effect was studied in terms of solute solvent and solvent solvent interactions. |
S0021961420304584 | The determination of equilibrium solubilities of thiamethoxam in solutions of 1 4 dioxane water N N dimethylacetamide water dimethyl sulfoxide water and acetonitrile water was carried out through the shake flask method from 278.15 to 323.15K under 101.2kPa . The relative contributions of solventsolvent and solutesolvent interactions on the drug solubility variation were studied via the analysis of linear solvation energy relationships . The significant contributions to the solubility variation were the cavity term and dipolarity polarizability term in aqueous solution of 1 4 dioxane and cavity term in aqueous solutions of DMAC DMSO acetonitrile . The inverse KirkwoodBuff integrals were employed to investigate the preferential solvation in light of several solution thermodynamic properties . The preferential solvation parameters for 1 4 dioxane DMAC and acetonitrile presented positive values in the three aqueous solutions within intermediate and 1 4 dioxane DMAC acetonitrile rich compositions demonstrating that the drug thiamethoxam was solvated preferentially by 1 4 dioxane DMAC acetonitrile . It is conjectured that in these regions thiamethoxam serves as a Lewis acid with the 1 4 dioxane and DMAC molecules while for the mixture the preferential solvation could be attributed to polarization effects . Moreover the solubility data in mole fraction was mathematically described by the vant HoffJouyban Acree model and Jouyban Acree model attaining the average relative deviations no more than 6.67 . | Thiamethoxam solubility in four aqueous solutions was determined and mathematically described. Preferential solvation of thiamethoxam were studied IKBIs method applied to solubility. Solvent effect upon solubility variation was inspected via KAT LSER model. |
S0021961420304754 | The solubility of oxaprozin in thirteen organic solvents ethanol n propanol n butanol n pentanol methyl acetate ethyl acetate n propyl acetate n butyl acetate n amyl acetate N N dimethylacetamide N N dimethylformamide dimethyl sulfoxide was determined using a laser monitoring method at atmospheric pressure in this work . The measured temperature range for all selected solvents is 278.15K to 323.15K except DMSO 293.15K to 323.15K . Through the entire studied temperature range the results turned out that oxaprozin solubility in selected solvents has a positive correlation with temperature variation . Four mathematical models were employed to correlate the solubility data including two empirical models and two activity coefficient models with the modified Apelblat model giving the best regression . Solubility order of oxaprozin in thirteen solvents was analysed by using the Hansen solubility parameter and the solvent effect was investigated through correlating oxaprozin solubility in selected solvents based on KAT LSER model . Moreover according to vant Hoff equation thermodynamic properties including apparent standard molar enthalpy change | Solubility of oxaprozin in thirteen pure solvents was measured. Hansen solubility parameter was applied to analyze the solubility order. KAT LSER model was applied to analyze the solvent effect. Solubility data was correlated by modified apelblat model h model NRTL model UNIQUAC model. Thermodynamic properties of the solution were calculated. |
S0021961420305073 | A method for implementing Active Microwave Thermography for use in determining molecular dipole moments is reported . Specifically the experimental setup along with a mathematical model for determining the dipole moment for deionized water is reported herein . The thermal and spatial resolution of the camera is shown to be of utmost importance in providing statistical and regional relevance respectfully of the properties of the material being studied . Deionized water in particular was studied in order to provide foundational knowledge for the veracity of using AMT in determining dipole moment values and representative values are reported herein . In order to extend the technique to more localized regions and composite systems a more complex model and upgraded hardware are required . | First ever use of Active Microwave Thermography AMT to measure the Molecular Dipole Moment. Creation of a model to image the dipole moment shows adequate temperature resolution is required. Measurements made on deionized water. |
S0021961420305097 | 2 3 3 3 tetrafluoropropene has been regarded as a promising alternative refrigerant and gained increasing interesting due to its environmental friendly properties . The introduction of HFO1234yf requires knowledge of the accurate thermophysical properties . The accurate speed of sound data is important for the improvement of the dedicated equations of state and the application in energy conversion system . The speed of sound in gaseous phase for HFO1234yf was measured by means of the acoustic resonance method using a fixed path cylindrical resonator . Measurements were conducted in the temperature range from 308K to 370K with pressures up to 1MPa . The speed of sound was obtained from the accurate measurements of acoustic resonant frequencies after being corrected for the perturbations from the viscous and thermal boundary layers the gas filling duct acoustic transducers and the shell motions . A total of 116 speed of sound data points were obtained with an expanded uncertainty less than 1.410 | New speed of sound data for HFO1234yf in the gaseous phase are reported. Measurements were carried out using the cylindrical acoustic resonator. Isobaric ideal gas heat capacities for HFO1234yf were deduced. |
S0021961420305103 | Thermal conductivity measurements of eight binary refrigerant mixtures were conducted in the homogeneous liquid and vapour phases with the transient hot wire technique . The temperature range of the measurements spanned from | Measuring thermal conductivity of refrigerant blends. New thermal conductivity data for CO. mixtures with HFCs and HFO 1234yf. Improving the models used by NISTs REFPROP 10 software package. Evaluating the predictive capabilities of the extended corresponding states models. |
S0021961420305115 | The present research work proposed the mole fraction solubility and mixing thermodynamic properties of piperonylonitrile in different binary solvent mixtures such as ethanol at | Solubility of piperonylonitrile was measured by laser monitoring method. The miscibility of piperonylonitrile in mixed solvents was revealed by Hansen solubility parameter. Experimental solubility was regressed and analyzed by four thermodynamic models. Mixing thermodynamic properties of piperonylonitrile were got by Wilson model. |
S0021961420305139 | Diethylamine ethyl acetate and triethylamine are usually applied to synthesize an important flame retardant of vinylphosphorus which has high ability to retard flames low toxic content and good washing durability . The isobaric VLE data of and system were determined at 101.3kPa for industrial separation . A minimum azeotrope was discovered at | Determine the VLE data of the unknown system molecular dynamics analysis. In our preliminary experiments we found that ethyl acetate and triethylamine had the lowest azeotrope and it was difficult to obtain high purity ethyl acetate from the reactive system. When the liquid molar fraction of diethylamine is greater than 0.4687 the azeotrope of the ethyl acetate triethylamine system can be eliminated. The molecular dynamics method was used to analyze the reason why the azeotropic point disappeared. The results showed that the van der Waals effect and electrostatic effect around ethyl acetate after the addition of diethylamine were the main reasons for the disappearance of the azeotropic point of the ethyl acetate triethylamine system. |
S0021961420305152 | The main objective of this work was to report the mole fraction solubility of rutaecarpine in four binary solutions of methanol water isopropanol water acetone water and ethanol water acquired through the saturation shake flask technique . All experiments were conducted at temperatures from 283.15K to 323.15K . The maximum solubility was observed in the pure solvent of methanol ethanol isopropanol acetone for each solution . The achieved rutaecarpine solubility in mole fraction was mathematically described by two common co solvency models namely Jouyban Acree model and vant Hoff Jouyban Acree model . The calculated relative average deviations were no more than 6.78 and root mean square deviations no more than 23.6910 | Rutaecarpine solubility in four binary aqueous solutions was experimentally acquired. Solubility data was correlated by Jouyban Acree and vant Hoff Jouyban Acree models. Preferential solvation of rutaecarpine in four mixtures were derived via IKBIs method. Solvent effect upon rutaecarpine solubility variation was studied by KAT LSER model. |
S002196731930812X | Multi linear gradients are a convenient solution to get separation of complex samples by modulating carefully the gradient slope in order to accomplish the local selectivity needs for each particular solute cluster . These gradients can be designed by trial and error according to the chromatographer experience but this strategy becomes quickly inappropriate for complex separations . More evolved solutions imply the sequential construction of multi segmented gradients . However this strategy discards part of the search space in each step of the construction and again can not deal properly with very complex samples . When the complexity is too large the only valid alternative for finding the best gradient is the use of global search methods such as genetic algorithms . Recently a new global approach where the level of detail is increased along the search has been proposed namely Multi scale optimisation . In this strategy cubic splines are applied to build intermediate curves to define any arbitrary solvent variation function . Subdivision schemes are used to generate the cubic splines and control their level of detail . The search was subjected to a number of restrictions such as avoiding long elution and favouring a balanced peak distribution . The aim of this work is evaluating and comparing the results of GAs and MSO . Both approaches were tested with a set of 14 diuretics and probenecid eluted with acetonitrile water mixtures using a C18 column . Satisfactory baseline resolution was obtained with an analysis time of 1516min . We found that GAs optimisation offered results equivalent to those provided by MSO when the penalisation parameters were included in the cost function . | Multi scale optimisation MSO is compared with Genetics Algorithms GAs . Long analysis times and excessive steeped slopes close to the peaks are penalized. Good agreement between experimental and predictions and balanced peak distributions. GAs with penalisation parameters found similar separations to MSO. Competitive method for screening 14 diuretics probenecid and a degradation product. |
S0021967319308131 | We have used gas chromatographic retention data together with other data to obtain Abraham descriptors for 30 terpene esters . These include the air water partition coefficient as log | Chromatographic data used to determine descriptors for terpene esters. Descriptors then used to obtain physicochemical and environmental properties. These include water solvent and air solvent partition coefficients. These include human odor detection thresholds. |
S0021967319308143 | Three different applications of travelling heating zone reactor chromatography for the downstream processing of monoclonal antibodies are described . mAb containing feedstocks were applied to a fixed bed of the thermoresponsive rProtein A matrix Byzen Pro contained in a bespoke column fitted with a travelling heating device encircling a narrow section of the column . For the demonstration of continuous concentration uninterrupted loading of 1.0g L mAb in a pH 8 binding buffer was synchronized with 5 repeated movements of the heating zone along the columns full length at a velocity of 0.1mm s. Elution of mAbs was induced solely by the travelling heating zones action each full movement generating a sharp concentrated elution peak accompanied by a small transient mAb concentration dependent dip in conductivity . Quasi steady state operation occurred from the third elution onwards delivering a mean mAb concentration of 4.9g L and process yield 93 . Quasi continuous separation of the target mAb from bovine serum albumin BSA was achieved by cyclically alternating the feeding of the mAb BSA feedstock with that of the binding buffer alone supply of the latter was timed to coincide with movement of the heating zone . Accurate coordination of the heating zones travel and switching from feed to buffer permitted quasi steady state collection of sharp peaks of mAb in high purity and yield in 4.5fold concentrated form with BSA exiting in the flow through fractions between successive mAb elution peaks . Fully automated THZR mediated quasi continuous buffer exchange of 1.34g L mAb from a phosphate buffer pH 8 into a HEPES buffer pH 8 of slightly lower conductivity was performed over a 19h period by carefully timed switching from one feed solution to the other and back again whilst synchronising movement of the heating zone with feeding of the exchange buffer . Quasi steady state operation resulted in an average eluted mAb yield of 94.5 and concentration of 4.8g L. Triggering movement of the heating zone slightly ahead of the switch from mAb feed to exchange buffer permitted the positioning of mAb elution peaks in 9mL volume segments with the lowest recorded conductivity . Measurements of buffer exchange performance conducted with two protein free systems demonstrated that compared to tangential flow filtration in diafiltration mode which represents the state of the art technology for buffer exchange the THZR chromatography based approach affords a 60 saving in minimum volume of exchange buffer required to remove 99.9 of the original buffer . Combined far and near UV circular dichroism intrinsic fluorescence and thermal melting experiments showed that unlike conventional Protein A G affinity chromatography the conditions for THZR Protein A chromatography respect maintenance of a favourable structural profile for mAbs . | Gentle mAb purification using thermoresponsive chromatography. Three applications of a novel travelling heating zone reactor THZR . Continuous mAb concentration 5 fold high yield of 93 . Quasi continuous mAb separation from a second component with high purities 98 . Quasi continuous buffer exchange demonstrating potential exchange buffer savings. |
S0021967319308155 | Syringe filters are used to separate solids from liquids prior to analysis of poly and perfluoroalkyl substances . This is a critical step in sample preparation as losses of PFASs to the filter material can be significant and lead to underestimation . This study evaluated losses of 21 PFASs in three different matrices methanol MilliQ water and water containing 10mgL | Losses of 21 PFASs to five filtration materials were analyzed in three important matrices. PFAS losses to filters could significantly reduce the analytical performance. The largest PFAS losses were observed in MilliQ water and the least in methanol. In the water matrices losses to filters were larger for longer chained PFASs. Recycled cellulose and polyethersulfone filters were found to sorb the least PFASs. |
S0021967319308167 | A combined procedure based on using ultrasounds for target isolation followed by porous membrane protected micro solid phase extraction using a molecularly imprinted polymer as an adsorbent has been developed as a highly selective extraction and clean up procedure for isolating aflatoxins B1 B2 G1 and G2 from fish feed before ultra high performance liquid chromatography tandem mass spectrometry determination . Polymeric adsorbent beads have been synthesized by the precipitation polymerization method which guarantees a homogeneous particles size distribution and the integrity of the generated imprinted cavities . In addition polymerization was performed using a higher proportion of organic solvent in the porogen mixture which generates MIP particles adequate for interacting with targets dissolved in organic mixtures . These approaches led to a selective and high efficient pre concentration method for AFs . Ultrasound assisted extraction 10mL of 60 40 acetonitrile 0.1M KH | New insights regarding the presence of aflatoxins in fish feed suggests the need for aflatoxins control in the aquaculture sector. Selective aflatoxins pre concentration clean up for reliable HPLC MS MS analysis. Fast and low cost sample pre treatment for aflatoxins assessment in fish feed and other feed and foodstuff. |
S0021967319308179 | Microcystins are cyclic heptapeptide toxins produced by various cyanobacterial genera that are toxic to both animals and humans . In this study a novel strategy was proposed for the quantitation of nine MCs and Nodularin R in lake water using UHPLC MS MS under negative ionization mode in which only centrifugation was employed during sample preparation . As a result limits of quantification ranging from 0.05 to 0.1g L for all studied compounds were obtained in water samples which were lower than the results obtained using positive ionization mode . Additionally validation was performed by spiking three different levels of MCs at 0.05 or 0.1 0.5 1.0g L . Recoveries ranged from 88.6 to 101.8 and intraday and interday variability were lower than 12 and 14 respectively for all targeted compounds . Furthermore the proposed method was applied to investigate microcystins contamination in fifty lake water samples collected in different regions in China . As a result MC LR MC RR MC YR MC WR MC LW MC LA MC LY and MC HilR were detected in lake water samples at trace level ranging from 0.06 to 0.37g L. The obtained results indicated that it was necessary to monitor the presence of MCs in lake water especially during regular cyanobacterial blooms during warmer months . | A validated UHPLC ESI MS MS method for the quantitation of nine microcystins and Nodularin R in lake water was developed. Only centrifugation was adopted during sample preparation which significantly increase sample throughput. The developed method was applied to investigate microcystins contamination in five lakes from China. |
S0021967319308192 | Table olives contain a wide range of polyphenols responsible for protective effects on health that have been associated with a lower prevalence of chronic diseases . A new method to identify and quantify these compounds in table olives by means of methanol ethanol extraction followed by LC ESI MS MS has been developed and validated . The chromatographic column Eclipse XDB C18 never used before in this kind of application provided the best results using Milli Q water with 0.025 acetic acid and acetonitrile with 5 acetone as eluents . This method allows the quantification of 17 polyphenols namely hydroxytyrosol tyrosol salidroside hydroxytyrosol acetate catechol vanillic acid caffeic acid | Fast method was developed to analyse table olives polyphenols by liquid extraction. Polyphenols from 5 classes were determined in 9min with novel LC ESI MS MS method. Validation results gave good recovery linearity precision and high sensitivity. 15 phenols were found in Marfil table olives mainly hydroxytyrosol HT and tyrosol. |
S0021967319308209 | Nakai is used as a traditional Chinese medicine . However very limited information is available on its effective components . Traditional procedures for discovering natural bioactive compounds especially for minor ones are usually time consuming and labor intensive . Therefore an efficient approach using ultra high performance liquid chromatographyquadrupole time of flight tandem mass spectrometry combined with multicomponent knockout and bioactivity evaluation was developed to obtain more information about the bioactive constituents in | Compounds in. were profiled by UHPLCMS MS with component knockout. A total of 93 compounds were identified or tentatively identified in. Eighty two of them have not been reported in this plant including a new compound. Sixty four compounds exhibited antioxidant activities screened by DPPHUHPLCMS. A new antioxidant brainin D was isolated and unequivocally identified. |
S0021967319308210 | It is challenging to achieve absolute quantitation and accurate identification with mass spectrometry imaging techniques . The issues facing these techniques include the uncertainty of sampling and ionization efficiencies in a localized environment the difficulty in defining the concentration of spiked standard on tissue and the low identification capability of MS in distinguishing isobaric compounds . In this study we coupled continuous flow liquid microjunction surface sampling with ultrahigh performance liquid chromatography MS for quantitative MSI of brain tissue . LC separation could increase the dimensions of identification and reduce the matrix effects in the tissue . A new LMJSS extraction solvent was developed to achieve exhaustive surface sampling therefore direct internal standard addition in the extraction solvent could be used for spot to spot absolute quantitation . The results showed that sphingolipids were successfully separated from their isobaric counterparts with LCMS and 10 sphingolipids were identified and imaged in brain tissue . The matrix effects in different locations of brain tissue with the new solvent were all in the range of 80 150 . Compared with the traditional LMJSS solvent the new solvent led to higher detection coverage and 6 10 fold higher sensitivity for 6 identified metabolites in brain tissue . Moreover extraction efficiencies of 8098 for targeted sphingolipids in brain tissue were obtained with the new solvent which allowed direct standard addition in extracts for absolute quantitation . Finally the absolute quantitation results with LMJSSLCMSI were compared with those using traditional bulk tissue extractionLCMS and similar quantitation results with these two methods were obtained for sphingolipids . The absolute quantitative spatial distributions of targeted metabolites largely matched previously reported results . The method was applied to a study on the quantitative spatial changes of sphingolipids and creatine in brain after traumatic brain injury . The biological replicate results showed that 2 metabolites had significant changes after TBI in several specific regions of brain tissue . | Continuous flow LMJSS was coupled with LCMS for quantitative MSI of brain. Complete extraction of sphingolipids from brain was achieved by a new LMJ solvent. Isobaric peaks were distinguished with LC for more accurate identification. Quantitation results of LMJSS LC MSI were validated with traditional LCMS. |
S0021967319308222 | Thermal papers significantly contribute to contamination of paper material cycles and the environment with substances of toxicological concern . In particular they contain color developers like endocrine disrupting bisphenols in typical concentrations of about 12 percent per weight . Bisphenol A was used as the common color developer over the last decades but it will be restricted for thermal paper application in the European Union to a limit of 0.02wt from 2020 onwards . Consequently a variety of BPA substituents such as bisphenol S and its derivatives gain importance in thermal paper application . In this study a rapid reliable and cost effective method for identification and quantification of BPA alternative color developers and related substances like sensitizers is presented based on HPLC separation coupled with diode array detection and Corona charged aerosol detection . Quantification was performed with regard to the intended use of the substances in thermal papers . Besides traditional UV external calibration using reference standards alternative quantification approaches in particular UV chromophore concentration for BPS derivatives and CAD universal response technique for low volatile color developers were applied and compared in order to allow quantification without reference substances . A market analysis for intended used color developers and sensitizers was performed on thermal paper samples collected in Germany during 2018 and 2019 . Pergafast 201 was the most common color developer with concentrations above 0.02wt followed by BPA BPS and other BPS derivatives known as D8 D 90 BPS MAE and TGSA that are mainly present in adhesive labels . Sensitizers were determined in over 90 of the samples . | Fast separation of 18 analytes color developers sensitizers dyes in 10min. Quantification without references via UV chromophore concentration and Corona CAD. Analysis of 211 thermal paper samples from the German market 2018 2019. Determination of color developers as functional components 0.02wt . Color developers Pergafast 201 BPA BPS D8 BPS MAE D 90 TGSA. |
S0021967319308234 | Plants are an important source of natural iridoids . This study demonstrates for the first time the acetylcholinesterase inhibitory activity of iridoids belonging to the class of antirrhinosides . As iridoids distinguish the chemical composition of most species of the Plantaginaceae family the active AChE inhibitors were investigated in the hydro alcoholic extract of | HPTLC EDA hyphenation leads to isolation of new iridoids. Antirrhinoside iridoids possess promising AChE inhibition activity. A proof of concept for AChE inhibitory potential of iridoids was shown. Structure elucidation of the active metabolites based on HRMS MS and NMR was elaborated. Influence of the structural components on AChE inhibition was discussed. |
S0021967319308246 | A novel approach based on the use of desirability functions is presented for the robustness assessment of liquid chromatographic separations as derived from computer assisted methods development processes . The approach is based on generally accepted hypothesis that a robust separation procedure will be inert to small random variations of the operational variables typically encountered in the day to day routine analytical practice . This means that peak positions along the chromatograms must keep standstill or move insignificantly when operational variables are not intentionally changed . Thus the degree of peak positions variation as evaluated from mathematical retention models can be used to assess the robustness of the developed procedures before testing the actual performance experimentally . In the approach proposed this assessment is obtained by fixing a bilateral partial desirability window around each peak in the simulated chromatogram . The whole chromatogram robustness is characterized by an overall desirability value calculated as the geometric mean of the partial desirability windows evaluation . An added advantage of this approach is that the robustness value calculated is normalized between zero and one and thus easy to interpret . Thus when chromatograms are simulated and small random variations are introduced into the operational factors of the model values for the overall desirability close to one means that the procedure performs robustly . On the contrary low values for the overall desirability clearly indicated a serious lack of robustness . When used in conjunction with the Pareto optimality approach as shown here this robustness assessment strategy allows testing several Pareto front solutions before the final experimental testing which is always needed . In this way a dramatical reduction of the experimental effort is obtained . Although the approach is theoretically applicable to any chromatographic separation examples of reversed phase liquid chromatographic procedures are used to show the performance of the proposed methodology . | Novel approach to assess the robustness of LC procedures based on desirability functions. Bilateral desirability functions used for the first time in the assessment of LC separation robustness. Robustness assessment using compute assisted methods development approach. Sensitivity analysis and workable region evaluation previous to experimental verification. |
S0021967319308258 | At the borderline between size exclusion chromatography and interaction chromatography there is a special mobile phase composition and temperature at which polymer chains become chromatographically invisible . This point is termed as chromatographic critical point and chromatographic separations performed using these conditions are called liquid chromatography at critical conditions . LCCC is a powerful technique in the analysis of functional polymers and block copolymers . At these so called critical conditions molar mass discrimination of any specific homopolymer is suppressed rendering elution of whole range of molar mass at same elution volume . These conditions allow enhanced separation with regard to non critical segment either in exclusion or interaction regime of the polymer chromatography . This article is intended to critically discuss different parameters that can be maneuvered to improve separation and in turn characterization of non critical segment of block copolymers at LCCC . Different experimental parameters evaluated in this study include pore size of the column mobile phase composition temperature and gradients . These parameters can be adeptly adjusted to improve separation of non critical segment while keeping the other segment close to critical conditions . Current study demonstrates that pore diameter and mobile phase are the only practical variable that can be used for improvement of characterization of non critical block in the block copolymer while non critical block is in exclusion regime . On the other hand pore diameter of the column temperature solvent composition and gradients are important parameters that can be skillfully tuned for improvement of separation of non critical block while non critical block elutes in interaction regime . The above mentioned variations are evaluated for di block as well as tri block copolymers of A B A and B A B type . Moreover LCCC IC is especially important for analysis of poloxamers . | Liquid chromatography at critical conditions of polymers is an important method for polymer characterization. The important variable for improvement of separation in case of LCCC SEC include pore diameter and mobile phase composition. Separation in LCCC IC can be improved by careful selection of pore diameter mobile phase composition gradients and temperature. LCCC SEC is applicable to block copolymers in general while LCCC IC is a special situation applicable to poloxamers. |
S002196731930826X | A simple rapid and sensitive ultra high performance liquid chromatography with charged aerosol detector method was developed for firstly simultaneous determination of seven oligosaccharides including two pairs of linear oligosaccharides isomers and 3 high branched oligosaccharides as well as sucrose in | Oligosaccharides in. were firstly analyzed. UPLC CAD was developed for analysis of these oligosaccharides. The peaks of oligosaccharides were also identified by UPLC QTOF MS MS method. The developed method was used to evaluate the quality of |
S0021967319308283 | In the present study during removal of minor impurities by twin column recycling chromatography with a solvent gradient a compressing band effect was generated to offset band spreading and retain the principal component band within one column . For real time monitoring a detector was mounted on line after the upstream column to monitor when the tail of the principal component was eluted from this column . When the conditions fluctuated the column were switched to ensure successful separation without the need to determine the adsorption equilibrium in advance . Optimization of the operating conditions revealed that increasing the solvent gradient improved pre impurity separation but impeded post impurity removal . Changing the feed volume within a certain range hardly affected separation of the impurities and increasing the number of cycles enhanced separation of the impurities . | Twin column recycling chromatography with solvent gradient removed minor impurities efficiently. The detector behind the upstream column could determine the columns switching. The band spreading was counterbalanced by the band compression. The displacement was strengthened to remove the minor pre impurities. |
S0021967319308301 | The separation of 14 chiral sulfoxides was systematically studied on 12 cellulose based chiral columns in acetonitrile and acetonitrile water mobile phases . Out of all monosubstituted methylphenylcarbamates of cellulose the one having a methyl moiety in position 3 showed more universal chiral resolving ability compared to 2 and 4 substituted derivatives . Out of disubstituted phenylcarbamates of cellulose the ones with methyl substituents showed higher enantiomer resolving ability compared to chloro substituted ones and substitution in positions 3 of the phenyl moiety was clearly advantageous . From disubstituted derivatives those possessing a combination of methyl and chloro substituents were advantageous compared to the ones having dimethyl or dichloro substituents . Chiral recognition ability of most chiral selectors towards studied sulfoxides was higher in pure acetonitrile compared to previously studied methanol . The effect of water addition to the mobile phase on analyte retention and enantioseparation was also quite different from that observed with methanol . In particular with aqueous methanol by increasing the water content in the mobile phase retention increased in most cases and the separation factor improved . In contrast with aqueous acetonitrile retention and separation factors decreased up to a certain water content in the mobile phase and then started to recover again for most of the studied analytes . | Separation of enantiomers of 14 chiral sulfoxides. Cellulose based commercial and non commercial chiral stationary phases. Effect of the structure of analytes on separation of their enantiomers. Effect of water content in the mobile phase on enantiomer separations. |
S0021967319308313 | Two new copolymer grafted silica stationary phases were prepared and employed in hydrophilic interaction chromatography . 2 ethyl methacrylate are copolymerized with itaconic acid and acrylic acid respectively via thiol ene click reaction on silica surface with deep eutectic solvents as new solvents . The obtained poly grafted silica and poly grafted silica were characterized by Fourier transform infrared spectroscopy elemental analysis and solid state | Two copolymer grafted silica stationary phases were prepared. Surface thiol ene click reaction on silica in deep eutectic solvents. Enhanced HILIC selectivity was obtained. |
S0021967319308337 | In this work we reported a simple two step method for the synthesis of magnetic mesoporous epoxy resin including one pot template free hydrothermal synthesis of nanoscale amine functionalized magnetic nanoparticles MN NH | A magnetic mesoporous epoxy resin MMER was prepared by a simple two step method. MMER had adequate magnetic responsiveness and thermal stability for rapid separation. MMER was used as magnetic solid phase extraction MSPE sorbent for enrichment of bile acids. MSPE combined with LCMS MS method was used to monitor 11 kinds of bile acids from serum. |
S0021967319308349 | The application of supercritical fluid chromatography with mass spectrometric detection was compared towards generic reversed phase liquid chromatography and hydrophilic interaction liquid chromatography for the analysis of urine with regards of ionization performance and analyte identification . The different chromatographic conditions were characterized with a selected set of 51 metabolites from different classes reported in the Human Metabolome DataBase and previously detected in human urine and or plasma . SFC using a diol column with a gradient of carbon dioxide CO | SFC shows complementarity to RPLC and HILIC for metabolomics. In SFCMS the ESI response of metabolites can be tuned addition of make up. SFCMS analysis of urine metabolites using data independent acquisition SWATH MS . |
S0021967319308350 | Polysorbates a group of nonionic surfactants are widely used as pharmaceutic excipient . Their quality and safety are closely related to their profiles including composition structure proportion and polyoxyethylene polymerization degree . However due to complex composition and similar skeletons it is difficult and time consuming to profile and identify them . There is no integrated strategy for routine control . In this paper an UHPLCHRMS method was established and 211 components belonging to 10 species in polysorbate 80 were identified based on their MS MS data and further confirmed by NMR . A mathematical model was then established to predict all possible components based on the good logarithmic relationship between the POE polymerization degrees and retention times of the components for the first time . A database of 853 detected and predicted components of polysorbate 80 60 40 and 20 was created . A novel rapid identification strategy was established for comprehensive polysorbate profiling by comparing the exact masses and RTs of the test peaks to the database . This novel strategy was employed to profile polysorbates in 14 pharmaceutic excipients and preparations . Approximately 200 components were identified and semiquantified in each sample and the number and content of components differed among these samples . | A fast strategy for comprehensive profiling of polysorbates by UHPLCHRMS. A mathematic model to identify components by relationship between POE. and RT. A database of 853 detected and predicted components of polysorbates. |
S0021967319308362 | A moment analysis method is effective for the kinetic study of intermolecular interaction and solute permeation at the interface of spherical molecular aggregates . Association and dissociation rate constants of intermolecular interactions or the rate constants of interfacial solute permeation can be determined on the basis of the moment theory from the first absolute and second central moments of elution peaks measured by affinity capillary electrophoresis or electrokinetic chromatography . In this study it was discussed how the experimental conditions concerning the concentration of ligand molecule or molecular aggregate should be optimized in ACE or EKC experiments in order to determine the rate constants as accurately as possible . At first peak broadening due to axial diffusion reaction kinetics of intermolecular interaction and mass transfer kinetics of interfacial solute permeation was quantitatively evaluated under hypothetical ACE or EKC conditions which were chosen on the basis of our previous studies . Second it was confirmed that some rate constants were determined in the previous studies from ACE and EKC data measured under appropriate experimental conditions . Then a procedure was considered for determining more accurate analytical results of the objective rate constants from ACE or EKC peaks experimentally measured . | Peak broadening in ACE and EKC was analyzed on the basis of moment theory. Influence of axial diffusion on band broadening was studied at different conditions. Influence of reaction kinetics and interfacial solute permeation was also studied. Validity of ACE and EKC experimental conditions in previous studies was discussed. A research procedure for kinetic study of ACE and EKC was considered. |
S0021967319308374 | Absolute quantification of B vitamins in milk is becoming imperative to correlate its impact on child human health . In today s world of changing food habits and environmental pollution there is concern if milk is what we think it to be . In the present work ultra high performance liquid chromatography mass spectrometry selected reaction monitoring methods have been developed and validated for quantitative estimation of 21 different B vitamins from a drop and B12 from 500L of milk . These two methods qualify all essential bio analytical parameters and are highly reproducible . By using these developed methods B vitamins in different fresh milk samples from cow goat buffalo and pasteurized cow milk each 10 and total | For the first time 21 B vitamins were quantified from miniscule volume of milk. Three different fresh milk samples from cow goat buffalo were compared. Total choline is the highest and vitamin B8 is the lowest in all milk samples. Inverse correlation between vitamin B2 and B5 was observed in milk samples. Total B vitamin and B12 contents are higher in cow milk compared to other two. |
S0021967319308386 | Mesoporous structured molecularly imprinted polymers combined with restricted access materials were synthesized in this work then RAM M MIPs were used as adsorbents in matrix solid phase dispersion to extract chlorpyrifos residues from soil . The RAM M MIPs with mesoporous structure increased adsorptive capacity and accelerated adsorption rate . At the same time the RAM M MIPs with restricted access function showed good exclusion effect toward humic acid in the soil . In addition the characteristics of RAM M MIPs were measured and the optimal experimental conditions of MSPD were explored . In MSPD the extraction and clean up procedures can be finished simultaneously which saved the extraction time . The analyte eluted from soil was determined by LCMS MS . The recoveries were in the range of 93.5106.1 and the relative standard deviations were in the range of 2.85.7 at the spiked soil levels of 0.1010.00ngg | Mesoporous structured molecularly imprinted polymer M MIP was prepared. M MIP was modified with restricted access material RAM M MIP . RAM M MIP increased adsorptive capacity and accelerated adsorption rate. RAM M MIP showed good exclusion toward humic acid in soil. RAM M MIP with matrix solid phase dispersion for extraction of chlorpyrifos. |
S0021967319308398 | We propose a new capillary electrophoresis based open tubular immobilized enzyme microreactor and its application in acetylcholinesterase assays . The IMER is fabricated at the capillary inlet with the inner surface modified by a micropore structured layer . The use of IMER accomplishes the enzymatic reaction and separation detection of the products in the same capillary within 3min . The feasibility of the proposed method is evaluated via online analysis of the activity and inhibition of AChE enzymes . Such method exhibits good reproducibility with relative standard deviation of less than 4 for 20 runs and the enzyme remains over 82 of the initial activity after usage of 7 days . The IMERs are successfully applied to detect the organophosphorus pesticide paraoxon in three types of vegetable juice samples with a limit of detection of as low as 61ngmL | Novel CE IMER is fabricated based on 3D micro porous layer open tubular column. Enhanced enzyme loading amount due to large surface area of micro porous layer. CE IMER exhibits excellent reproducibility and stability for enzyme assays. Successful application of CE IMER for detecting organophosphorus pesticide. |
S0021967319308416 | Accurate quantitation of aldosterone is critical for the clinical detection of hypertension . However no reference intervals for aldosterone in healthy volunteers and patients with hypertension have yet been established using highly sensitive methods with a wide linear range based on low plasma volumes . We developed a modified ultra performance liquid chromatographytandem mass spectrometry method for the quantitation of aldosterone and established reference intervals for healthy volunteers and patients with hypertension . We measured aldosterone by UPLCMS MS in human plasma samples . We established a reference range for aldosterone based on blood collected midmorning from 888 patients with hypertension and 258 seated normotensive subjects . The linear range was 105000pg mL | Reference intervals of aldosterone for healthy volunteers were established. Aldosterone levels in 888 hypertensive patients were measured. We prepared samples with 90L plasma and measured aldosterone using UPLCMS MS. Our UPLCMS MS method had higher sensitivity and wider linear range. |
S0021967319308428 | We report on a study on the use of 2D LC in industry wherein we maximized the peak capacity by serially coupling up to six 15cm long columns in the 1st dimension . For the considered aromatic amine oligomer sample the combination of reverse phase pentafluorophenyl column providing selectivity based on interaction in the 1st and a more retaining reverse phase polymeric C18 column in the 2nd dimension proved to give the highest orthogonality calculated to be 0.82 . Whereas a | 900 peaks in an industrial aromatic amine sample could be separated using 2D LC. Six coupled columns 2.6m150mm were used in. D. 1200bar instrumentation was used for each dimension. Peak capacity was over 10 000 was after correcting for undersampling and orthogonality. Going from 1 to 6 columns for. D leads to 940 instead only 350 detected components. |
S0021967319308453 | Pentacyclic triterpenoids possess high biological activity including antitumor anti inflammatory antiviral and hepatoprotective properties and are widespread in a plant biomass . Due to significant differences in polarity and other physicochemical properties the simultaneous determination of different classes of PCTs by the methods of reversed phase liquid chromatography is difficult . In the present study we proposed a new approach to chromatographic separation of such compounds based on the use of a stationary phase with a mixed retention mechanism combining hydrophobic weak anion exchange and hydrophilic interactions . The use of the Acclaim Mixed Mode WAX 1 column and tuning the selectivity by changing the contributions of different types of analytestationary phase interactions allowed the separation of 10 PCTs belonging to four different classes during 7.5min in isocratic elution mode . The combination of this approach with atmospheric pressure chemical ionization tandem mass spectrometric detection and pressurized liquid extraction of analytes with methanol allowed to develop a rapid accurate and highly sensitive method for analyzing PCTs in plant tissues with a total duration of the analytical cycle of not more than 40min . It provides the detection limits in plant biomass extracts of 312gL | Mixed mode stationary phase was used for pentacyclic triterpenoids PCTs separation. Hydrophobic anion exchange and hydrophilic interactions contribute to retention. Selectivity of analysis was optimized by tuning the contributions of these mechanisms. Method for rapid analysis of monools diols and triterpenic acids was developed. Ten PCTs were quantified in plant extracts by mixed mode HPLCMS MS. |
S0021967319308477 | Fast gas chromatography that leverages the high chromatographic efficiency of narrow bore capillary column technology and temperature programming was successfully integrated with a third generation low void volume 3D printed two stage microreactor . Effective management of extra column effect and the capability to perform post column backflushing were achieved with the incorporation of a recently commercialized electronically controlled pneumatic switching device and a deactivated metal three way microdevice . | Post column reaction with flame ionization detection for one dimensional high speed gas chromatography. Elimination of multi component and multi level calibrations with carbon compound indendepent response. Compatibility with high resolution gas chromatographic columns having internal diameters as narrow as 100m. A three way microdevice interface for effective reduction of extra column effects. Advanced microfluidic pneumatic switching device for accurate low flow control. |
S0021967319308489 | Linolenic acid and its most important positional isomer linolenic acid are essential fatty acids . Therefore ALA and GLA rich edible oils hold great potential in human and animal nutrition as well as in nutraceutics and cosmetics . Quality control and nutritional validation of oil products is thus of increasing importance . In the present study the cellulose tris based chiral stationary phase was successfully used for separation of ALA and GLA a major challenge in the liquid chromatography of these isomers . The chromatographic conditions were firstly optimized on a HPLC system with UV detection and the use of a reversed phase eluent system made up of aqueous 10mM ammonium acetate acetonitrile 40 60 v v | and Linolenic acids ALA and GLA are involved in several metabolic processes. ALA and GLA rich oils hold a potential as source of nutrition or in cosmetics field. An immobilized cellulose based CSP allows the RP separation of ALA GLA. The separation method was optimized and transferred to a LCMS MS platform. The proposed innovative method was applied to analyze edible oils and human plasma. |
S0021967319308490 | The present study reports on the analysis of different factors affecting the magnitude of the peak capacity for intact protein separations conducted in gradient reversed phase liquid chromatography . Experiments were conducted using a 200m i.d . capillary styrene | The maximum peak capacity is achieved at a flow rate 20 x higher than the optimal van Deemter flow rate. The gradient volume has an important impact on overall peak capacity. The use of TFA as ion pairing agent leads to better mass loadability compared to FA. |
S0021967319308507 | In this work the suitability of gas chromatography mass spectrometry and liquid chromatography tandem mass spectrometry for the multi class determination of different families of neutral per and polyfluoroalkyl substances such as fluorotelomer olefins alcohols and fluorooctanesulfonamides and sulfonamido ethanols was investigated and compared . Regarding GCMS the use of a semi polar GC column allowed the adequate separation of all the compounds while chemical ionisation of positive ions as ionisation technique provided the best responses . Concerning UHPLCMS MS atmospheric pressure chemical ionisation and photoionisation sources allowed the ionisation of all studied neutral PFASs including FTOs for the first time . High vaporizer temperatures and acetonitrile water mobile phase mixtures were required to favour the ionisation of FTOs with adequate ionisation for FTOHs FOSAs and FOSEs . The chromatographic separation performed on a totally porous column allowed the successful separation of the four families of neutral PFASs . After comparing the performance of the studied methods the highest detectability was achieved using UHPLCAPCIMS MS and it was chosen in combination with a solid phase extraction procedure for the analysis of neutral PFASs in water samples . The whole method provided low limits of detection 0.0036gL | CI and a semi polar column provided the best GCMS conditions for all the compounds. Negative ion APCI provided the lowest LODs for the target compounds by LCMS. For the first time FTOs were ionised by atmospheric pressure ionisation sources. UHPLCAPCIMS MS method allowed the multi class determination of neutral PFASs. The presence of neutral PFASs in river waters remains constant through the time. |
S0021967319308635 | Porous organic frameworks are an exciting emerging type of porous organic materials in which molecular building blocks are linked by covalent bonds . POFs usually have high thermal and chemical stability large surface area artificially regulated pore size distribution and abundant functional groups which are considered to be ideal and efficient adsorbent for diverse compounds . They are an excellent alternative for sorbents coating based sample pretreatment techniques . In this review the application of various POFs in trace analysis is discussed in terms of pretreatment techniques including solid phase extraction magnetic solid phase extraction solid phase microextraction capillary microextraction and stir bar sorptive extraction . The POFs based sorbents coatings are reviewed with the focus on the construction process comparison among POFs and between POFs and common sorbents adsorption mechanism for specific analytes and the adsorption performance in trace analysis . Current research status indicate that much effort would be paid on further exploration of the relationship between the special properties of POFs and the adsorption behavior directional design and synthesis of POFs involved sorbents coating for trace analysis of organic substances and elemental species and the development of POFs involved analytical methodologies for quantification of interest analytes . | Porous organic frameworks POFs have high surface area and good stability. POFs are good alternatives for SPE sorbents or SPME MSPE coatings. Construction methods for POFs involved sorbent coating are summarized. Application of POFs involved methods for trace analysis are reviewed. Adsorption mechanism of POFs for interest analytes is discussed. Current problems are discussed along with perspectives in future development. |
S0021967319308659 | The presence of a liquid stationary phase in liquidliquid chromatography allows for high versatility of operation as well as adaptability to different sample types and separation tasks . LLC also known as countercurrent chromatography or centrifugal partition chromatography offers the user a variety of operating modes many of which have no direct equivalent in conventional preparative liquidsolid chromatography . These operating modes have the potential to greatly improve LLC separation performance compared to the standard classical isocratic batch injection mode and they often require minimal to no addition of equipment to the standard set up . However reports of the use of alternative LLC operating modes make up only a fraction of the literature . This is likely due at least in part to the lack of clear guidelines and methods for operating mode and parameter selection leaving alternative process options to be avoided and underutilized . This review seeks to remedy this by providing a thorough overview of the available LLC operating modes identifying the key characteristics advantages and disadvantages and areas of application of each . Additionally the equations and short cut models aiding in operating mode and parameter selection are presented and critiqued and their notation is unified for clarity . By rendering LLC and its alternative operating modes more accessible to current and prospective users it is hoped to help expand the application of this technology and support the achievement of its full potential . | Standard extrusion flow reversal and continuous operating modes discussed. Critique and unification of published design equations and short cut models. Operating mode selection based on sample and separation goal. Preliminary separation design with simple equations. |
S0021967319308660 | A semi automated online platform was established successfully for preliminary screening of potential active flavonoids of traditional Chinese medicines in multicomponent system . Online coupling of the | The online coupling of Ussing chamber SPEHPLC platform was actualized at first time. The platform was used to screen the potential active flavonoids of TCMs. A total of 14 flavonoids were identified in HQ and HZ by UPLCMS MS. 12 flavonoids were screened as the active components of HQ and HZ by online platform. |
S0021967319308672 | The off flavor compounds geosmin and 2 methylisoborneol are well known to impact the quality of farmed freshwater fish species but little is known about off flavors in marine aquaculture . To begin addressing this knowledge gap a method for determining geosmin and 2 MIB using LC with atmospheric pressure chemical ionization MS detection was developed . While 2 MIB was readily detected using LC APCI MS geosmin exhibited on column degradation that was independent of column chemistry and could not be eliminated . Optimized conditions were identified that balanced the separation and ionization efficiency of 2 MIB and geosmin while minimizing geosmin degradation but the overall method sensitivity for geosmin was reduced by the on column losses . The method was used with direct aqueous injections to determine the volatilization rates of geosmin and 2 MIB at ppb levels during aeration under laboratory conditions in both salt water and pure water to simulate marine and fresh water aquaculture respectively . The volatilization rates of both compounds were 30 faster in salt water than in fresh water with or without aeration but aeration was found to enhance the rate by a factor of 2.5 in both water types . The LC APCI MS method was combined with stir bar sorptive extraction to achieve greater sensitivity for determining off flavors in recirculating aquaculture system water . Using SBSE LC APCI MS the LODs for geosmin and 2 MIB were 70ng kg and 6ng kg respectively . The on column losses resulted in a relatively high LOD for geosmin that renders this method unsuitable for determining geosmin at the low ng kg levels expected in RAS . SBSE using both grab water samples and an in situ diving unit were used to evaluate 2 MIB levels in the culture water of two separate marine RAS that were supporting the growth of European sea bass but had differing levels of water treatment . 2 MIB was readily detected using both SBSE approaches in the RAS with less sophisticated treatment when the animal stocking density was at its highest 50kg m | First LC APCI MS method for determining geosmin and 2 MIB was developed. Method is sensitive for 2 MIB but has limited applicability for geosmin due to losses. Aeration enhances volatilization of geosmin and 2 MIB from both pure and salt water. SBSE LC APCI MS with grab and in situ samples can determine 2 MIB in RAS water. The degree of water treatment in marine RAS influences 2 MIB levels in culture water. |
S0021967319308726 | Most adsorbent materials used for preconcentrating and thermally desorbing volatile and semi volatile organic compounds in portable or micro gas chromatographic instruments preferentially capture non polar or moderately polar compounds relative to more polar compounds . Here we explore the use of a known trigonaltripyramidal room temperature ionic liquid as a surface modifier for the graphitized carbons Carbopack B and Carbopack X with the goal of enhancing their capacity and selectivity for polar S VOCs . Breakthrough tests were performed by challenging tubes packed with 2.5mg of C B or RTIL coated C B with 13 individual S VOCs including several organophosphorus compounds and reference alkyl and aromatic hydrocarbons of comparable vapor pressures at concentrations ranging from 14 to 130mg m | With the RTIL capacities for polar e.g. organophosphorus vapors increased 2.5 . With the RTIL capacities for non polar vapors decreased 1126. Trends in capacity were strongly correlated with analyte vapor pressure. Trends in capacity were not well described by LSER models. |
S002196731930874X | We report the discovery preliminary investigation and demonstration of a novel form of differential flow modulation for comprehensive two dimensional gas chromatography . Commercially available components are used to apply a flow of carrier gas with a suitable applied auxiliary gas pressure | A simple and effective means to accomplish differential flow modulation is introduced. Total transfer unit duty cycle is achieved concomitant with full modulation. Commercially available components are used to construct the low cost modulator. Narrow peaks are produced yielding high signal enhancements. Separations of a 5 component test mixture a 90 component test mixture and a diesel fuel are provided. |
S0021967319308751 | The gaseous phase analyses of volatile organic compounds are an important challenge especially when these organics are formed in high vacuum environments 10 | The analytical system designed for VOCs analysis from vacuum environments is herein optimized. A cryofocusing system in the GC oven enhanced chromatographic resolution and sensitivity. VOCs recovery was noticably improved by increasing system pressure using Argon. The optimized system was applied to the analysis of photoprocessed interstellar ice analogs. |
S0021967319308763 | The main problem of poor water compatibility of molecularly imprinted polymers has been addressed in this study . A new facile and highly efficient approach was developed to obtain well defined hydrophilic molecularly imprinted polymer microsphere with excellent specific recognition ability toward Chenodeoxycholic acid in crude bile . Particularly it involved computational modeling to obtain a polymer network with high affinity for CDCA and addition of a hydrophilic crosslinker diacrylate200 to increase the hydrophilicity of the polymer surface . To our knowledge this study first report splitting method in molecular imprinting technology . By using the splitting method simulation time can be saved under the premise of ensuring accuracy . The adsorption experiments revealed that an optimized CDCA MIP exhibited better selectivity toward CDCA with inhibition of the nonspecific adsorption . The CDCA MIP possessed adsorption capacity of 49.86mgg | Chenodeoxycholic acid adsorbent was prepared by molecular imprinting technology. Simulation time can be saved by splitting method with acceptable accuracy. CDCA MIPs with polyethylene glycol partially inhibited the nonspecific adsorption. The adsorbent showed good adsorption capacity for CDCA from crude bile. |
S0021967319308829 | Velvet antlers have been used as medicines and nutraceuticals for over 2000 years . Meanwhile deer antlers are the only mammalian organs that can fully regenerate after annual shedding . The antler formation and regeneration rely on the stem cells resident in antlerogenic periosteum transplantation of which can induce ectopic antler formation . Here a comprehensive quantitative proteomic analysis of antlerogenic periosteal cells compared with the adjacent facial periosteal cells was carried out from both extracellular and intracellular perspectives . In this study the stable isotope labeling by amino acids in cell culture was applied to ensure the precision of quantification . Then the protein equalization strategy and reverse phase liquid chromatography separation in high pH were utilized to improve the depth of proteome profiling . Proteomics analysis of the conditioned media from AP and FP cells showed that significantly over expressed extracellular proteins in AP cells were involved in cell proliferation angiogenesis and neurogenesis . Combining the extracellular and intracellular proteomes we found several potential secreted proteins might regulate antler formation and regeneration such as SFRP4 and LUM . These results provide new insight into the underlying mechanism of antler formation and regeneration . | Proteome profiling of antler stem cells from both extracellular and intracellular. Overexpression of sFRP4 and LUM in AP cells shows their role in antler growth. Shed more light on CM of antler stem cells as a new resource for bioactive molecular. |
S0021967319308830 | This study introduces micrometric carbon strands as a suitable fiber for headspace solid phase microextraction . Compared to previous supports carbon fibers have mechanical flexibility wide thermal expansion and a large surface area which is an important factor in headspace solid phase microextraction . The electrophoretic technique was applied to modify the surface of stainless steel and carbon fibers with polypyrrole . Modified carbon fibers were used for extraction of 2 pentylfuran as a model analyte from patients breath and coffee samples . 2 PF belongs to the furan family which was suggested as a biomarker for | Micrometric carbon fibers CFs was introduced as a support for HS SPME. Electrophoretic technique was applied to modify surface of CFs with polypyrrole. Separation and analysis of the analytes was performed by GCMS. Effective parameters on extraction efficiency of 2 PF were studied and optimized. was used for extraction of 2 penthylfuran from patients breath and coffee. |
S0021967319308854 | Natural products and traditional medicines are used for treatment of various diseases and also to develop new drugs . However identification of drug leads within the immense biodiversity of living organisms is a challenging task that requires considerable time labor and computational resources as well as the application of modern analytical instruments . LCMS platforms are widely used for both drug discovery and quality control of TMs and food supplements . Moreover a large dataset generated during LCMS analysis contains valuable information that could be extracted and handled by means of various data mining and statistical tools . Novel sophisticated LCMS based approaches are being introduced every year . Therefore this review is prepared for the scientists specialized in pharmacognosy and analytical chemistry of NPs as well as working in related areas in order to navigate them in the world of diverse LCMS based techniques and strategies currently employed for NP discovery and dereplication quality control pattern recognition and sample comparison and also in targeted and untargeted metabolomic studies . The suggested classification system includes the following LCMS based procedures elemental composition determination isotopic fine structure analysis mass defect filtering | Analytical strategies employed in the natural products research are discussed. Dereplication and untargeted metabolomics workflows are decomposed to separate blocks. A von Koch star based classification of LCMS techniques is suggested. Recent advances of the analytical techniques for traditional medicine study are included. |
S0021967319308878 | In counter current chromatography the hydrodynamic motion of a two phase solvent system in the column coil is very important . There are some previous visualization studies on CCC using stroboscopic photography . As CCC separation is a continuous liquid liquid extraction process observing the distribution and movement of the solvent system on line will be helpful to understand the hydrodynamic behavior during the whole CCC separation process . In the present study a high speed imaging camera was employed to take videos of a running CCC bobbin . The dynamic motion and phase distribution of conventional quaternary solvent system hexane ethyl acetate methanol water and ternary solvent system dichloromethane methanol water were both investigated . Wave like mixing was observed in the area where the centrifugal force is minimum in different diameter columns . When the coil rotated the mixing zone was fixed at the minimum centrifugal force position . Several photographs of the rotating coiled tube were taken which revealed that the phase dispersion hardly changes once equilibrium is established . Finally the sample dispersion process was also recorded . These results will help us to understand the separation process in a CCC column coil and also present some more interesting questions related to separation efficiency which are shown in discussion part of this paper . | Mixing zone was located near to the proximal key node and traveled through the column. Every parts of bobbin went through a mixing settle process. Phase distribution hardly changed once hydrodynamic has been established. The sample diffusion was quite fast after injection which might cause low efficiency. |
S002196731930888X | This work examines the separation dynamics of monoclonal antibody monomer dimer mixtures by frontal analysis using ceramic hydroxyapatite CHT Type I and Type II columns . The binding capacity and selectivity are dependent on the CHT type and salt concentration . While the rate of protein adsorption on CHT Type I is slow and controlled largely by pore diffusion resulting in relatively poor separation adsorption on CHT Type II is much faster and better separation is obtained than with Type I . However comparison with predictions based on pore diffusion alone reveals the presence of additional resistances associated with adsorption and displacement kinetics . A spreading kinetics model assuming multiple binding configurations coupled with pore diffusion was developed to describe these effects and found to be in quantitative agreement with the frontal analysis results and able to predict the separation achieved for conditions outside the range of the experiments . To help validate the assumed mechanism isocratic elution experiments were also conducted at low protein loads . The chromatograms could be described by the solution of the spreading model coupled with pore diffusion in the linear region of the isotherm with parameters determined from the analytical expressions for the peak moments . This confirms that there is an increasing tendency to spread with slower kinetics as the salt concentration is decreased and binding strength is increased . | Frontal analysis separation of antibody monomer dimer mixtures on CHT columns. Adsorbent structure and mobile phase effects on transport and adsorption kinetics. Mechanistic model accounting for surface spreading describes column dynamics. |
S0021967319308891 | Biochemical and thermochemical processes are two pathways to convert lignocellulosic biomass into fuels and chemicals . Both conversion types produce aqueous complex samples containing many oxygenated chemical functions over a wide range of masses . Nowadays composition of these biomass products is still largely unknown especially their nonvolatile part mostly made of carbohydrates and their derivatives . In the present study size exclusion chromatography was investigated and applied on water soluble phase of a fast pyrolysis bio oil and on aqueous phase of pretreated wheat straw . An optimization of mobile phase composition using model molecules was necessary to limit non steric interactions and elute all chemical families . At the end separation of carbohydrates heterosides and aromatic species was performed . The chemical organization of SEC chromatograms was confirmed by coupling SEC with a Fourier transform ion cyclotron resonance mass spectrometer using electrospray ionization in the negative mode . On line SEC UV FT ICR MS hyphenation was a powerful tool to provide exact mass distribution of samples and get molecular formulae classed by chemical family . To go further the complementarity of SEC with reversed phase liquid chromatography was established with an off line comprehensive 2D LC analysis of the two samples . First 140 fractions were collected physically from SEC separation for each sample then each fraction was analyzed by RPLC hyphenated to an Ion Trap Time of Flight mass spectrometer using ESI in both positive and negative modes . This comprehensive approach combining 2D LC and high resolution mass spectrometry nearly doubled the number of peaks detected in comparison with 1D RPLC analysis and thus offered well resolved 2D contour plots considered as relevant analytical fingerprints of the aqueous phase of biomass samples . | Aqueous phases of a fast pyrolysis bio oil from sawdust and pretreated wheat straw. SEC on a low mass range 1000Da . On line SEC UV HRMS and chemical organization of chromatograms. Off line comprehensive SECRPLC UV HRMS. Fingerprints of samples through 2D multi detection contour plots. |
S0021967319308908 | A high performance liquid chromatography mass spectrometry technique hyphenated on line with an immobilized enzyme reactor was developed by the use of 3 known acetylcholinesterase inhibitors . This bioanalytical device allows qualitative comparison of the inhibitory strengths of AChE inhibitors . The AChE inhibitory strengths were evaluated and compared by the corresponding acetylcholine peak areas obtained after a chromatographic separation and the elution through the IMER . Only one injection of the analytes is needed to get this comparative analysis . This bioanalytical device was then applied to the extract of a natural plant | An innovative HPLC IMER MS bioanalytical device was established for high resolution screening HRS of AChE inhibitor. The relative inhibitory strengths of AChE inhibitor could be compared directly by comparing the inhibitor corresponding ACh peak area. A new natural AChE inhibitor dihydro latifaliumin C was firstly reported by the application of this HPLC IMER MS bioanalytical device to the. extract. |
S002196731930891X | A proteomic workflow for a simple loss less manual nano fractionation for low g sample amounts which avoids the need to dry down or transfer fractions to autosampler vials is shown to be feasible . It is demonstrated that the conventional procedure of drying samples down followed by reconstitution negatively affects the number of protein and peptide identifications . Furthermore these losses seem to disproportionately affect hydrophobic peptides from the drying down and reconstitution step . By collecting and concatenating the fractions while the outlet of the column is submerged in a small predefined volume of 0.2 formic acid the content of acetonitrile in the collecting vials was lowered such that it was compatible with direct injection for the online analysis . This additionally resulted in a time gain of approx . an hour for the total fractionation time . Acetonitrile concentrations up to 7.5 do not seem to compromise the chromatographic performance in the online analysis . Using as little as 2g digested HeLa lysate approx . 7000 protein groups could be easily identified with 2 or more unique peptides . This was the case when fractionation was performed at pH 10 as well as at pH 5.5 . | True loss less reversed phase fractionation using nano flow is feasible. Ability to collect fractions of 300nL manually. Simple dilute and shoot strategy to collect and analyze concatenated fractions. Improved number of peptide ID s through avoiding drying reconstitution steps. Mildly acidic reversed phase chromatography exhibits sufficient orthogonality. |
S0021967319308945 | In this study a novel phenylboronic acid polymeric monolith in polyether ether ketone tube was fabricated . The inner wall of PEEK tube was modified with mussel inspired polydopamine layer to firmly bond PBAPM so as to avoid the outflow of PBAPM from PEEK tube and improve the service life and application scope of PBAPM . The PBAPM was synthesized by initiator free ring opening polymerization based on our previous work . The boric acid groups provided BN coordination sites as well as the hydrophobic amino and epoxy monomers provided hydrophobic interaction sites . Due to the synergistic effect of hydrophobic interaction and BN coordination the PBAPM exhibited excellent binding amounts for nitrogen containing sulfonamides . In addition the PBAPM possessed excellent stability rigidity and permeability . Therefore the PBAPM was used as solid phase microextraction material for enrichment and separation of SAs from aqueous samples . The PBAPM SPME was optimized in detail and combined with ultra performance liquid chromatographytandem mass spectrometry analysis for simultaneous determination of 10 kinds of SAs from tap lake and river water . Using only 1mL of water samples limit of quantitation of SAs could reach 0.544.5ngL | A hydrophobic phenylboronic acid polymeric monolith PBAPM was fabricated in PEEK tubes. The PBAPM was applied in SPME of SAs based on hydrophobic interaction and BN coordination. PBAPM SPME combined with UPLCMS MS was used to monitor 10 kinds of SAs from aqueous samples. Using only 1mL of water samples limit of quantitation of SAs could reach ultra trace level. |
S0021967319308957 | Although around 90 years have passed since Richards and Loomis developed the first experiments in sonochemistry ultrasound is still awakening interest in the scientific community in particular in the Analytical Chemistry field as a result of the high number of benefits achieved which are also in accordance with Green Analytical Chemistry principles . In the last years and among the different reported applications an important number of works have arisen devoted to the synthesis of new materials to the development of sonoelectroanalytical sensors or to new spectroscopic approaches among others . Efforts are also being made to try to understand the real mechanism of such applications . This review article is aimed at providing a general overview of the different applications of ultrasound in Analytical Chemistry also briefly highlighting its fundamentals and traditional applications with a special emphasis on the most recent and challenging works that are still in the horizon of its near future . | The different applications of US in analytical chemistry are overviewed. Fundamentals and more traditional applications are also presented. US assisted synthesis of nanomaterials comprise a high number of applications. Sonoelectroanalytical sensors and new spectroscopic approaches are also of relevance. |
S0021967319308969 | The simultaneous use of nitrite and sorbate as preservatives in meat products may produce mutagenic compounds such as the ethylnitrolic acid and 2 methyl 1 4 dinitro pyrrole . We developed a sensitive analytical method with high metrological reliability . After assessing several extraction approaches and chromatographic separation modes a modified Quick Easy Cheap Effective Rugged and Safe approach was chosen for sample preparation which were analyzed by reversed phase liquid chromatography with C | Several sample preparation and chromatographic approaches were assessed. A modified QuEChERS and RP C. LCESI MS MS approach was fully validated. This method can quantitate ENA and DNMP traces in various processed meats. Positive results for ENA and DNMP carcinogens in meats were obtained. |
S0021967319308982 | Quantitative structure retention relationships analysis was applied to investigate the molecular retention mechanism of proteinogenic and non proteinogenic amino acids on the amino acid and peptide silica stationary phases . Twelve stationary phases with chemically bonded amino acids of different types glycine alanine phenylalanine leucine methionine aspartic acid and | The amino acids retention mechanism on the amino acid based packings was investigated. The QSRR was performed on materials differing in type length of amino acid sequence. Analysis showed that electrostatic interactions are prominent in retention process. Formation of hydrogen bonds is characteristic feature for peptide based columns. The derived QSRR models revealed good prediction potency for test set of analytes. |
S0021967319308994 | Tandem mass spectrometry in particular high resolution MS MS is able to provide element compositions and substructures for the detected signals . However it is still challenging to configure the whole structures | Optimum collision energy is an inherent molecular descriptor of a given compound. Optimum collision energy facilitates confidently structural annotation of CADs. Online energy resolved mass spectrometry was developed to acquire breakdown graphs for bond dissociations of interest. Optimum collision energy tightly correlates with the corresponding bond properties such as bond energy and length. Optimum collision energy is superior to CE. owing to specific bond property description. |
S0021967319309021 | A fully continuous downstream process represents one of the most interesting novel purification approaches in the biosimilars industry because it would enhance the production output while reducing the costs of complex biopharmaceuticals . Since it generally involves several chromatographic steps the selection of appropriate chromatographic columns is of utmost importance . In this study we compared several commercially available ion exchange membrane adsorbers for the removal of deoxyribonucleic acid host cell proteins and monoclonal antibody aggregates in flow through mode . Design of Experiments was employed to determine the optimal pH and conductivity conditions . We demonstrated that all the anion exchange membrane adsorbers were capable of removing DNA and HCPs from monoclonal antibody mixtures below the required threshold across a wide range of sample pH and conductivity values and that the HCPs normalized outlet concentration increases almost linearly with the loading being independent of the HCPs concentration . No significant differences in the profile of the adsorbed HCPs with respect to the membrane adsorbers were observed based on 2D electrophoresis analysis data although they exhibited different binding capacities . Cation exchange membrane adsorbers were also tested for the removal of aggregates . The Yamamoto model was used to determine the number of binding sites and estimate the conductivity range for efficient removal of aggregates while maintaining a high monoclonal antibody recovery . However the obtained range had to be further fine tuned experimentally due to displacement phenomena . Differences in the trends of binding site number with a change in the pH value for the tested cation exchange adsorbers indicate slightly different adsorption mechanisms . To obtain optimal process performance adjustments to the pH and the conductivity were required between the anion and cation exchange steps . | Implementation of membrane adsorbers for continuous impurity removal from Mabs. Displacement plays important role in determination of operating conditions. Different anion exchange adsorbers removes same HCPs but to different level. |
S0021967319309033 | In this work tetraalkylammonium amino acid ionic liquids were first applied to non aqueous capillary electrophoresis to establish synergistic systems with a conventional chiral selector native cyclodextrin . Excellent enantioseparations of some dansyl amino acid samples were achieved . A series of comparison experiments and a molecular docking study were performed to validate the synergistic effect of TAA AAILs and CD in NACE . Several interesting results were observed compared with previously reported chiral ILs related aqueous CE studies . In particular the direct enantioselectivity of TAA AAILs was observed for the first time by using it as sole chiral selector in NACE . This was an encouraging finding because it was the first direct and convincing evidence that AAILs were able to participate in the enantiorecognition process in the conventional chiral selectors based synergistic systems . The new TAA AAILs synergistic NACE system was further optimized in terms of alkyl chain length TAA AAILs concentration CD concentration electrolyte composition and applied voltage etc . Best enantioseparations of Dns AAs were obtained when 100mM CD and 10mM tetramethylammonium | Chiral ILs were first applied to NACE for enantioseparation. The direct enantioselectivity of TAA AAILs in CE was observed for the first time. Several interesting results were observed in the NACE compared with aqueous CE. Excellent enantioseparations were achieved for all Dns AAs. |
S0021967319309045 | A sensitive fast eco friendly ultrasound assisted liquidliquid microextraction in combination with hydrophobic deep eutectic solvent method was developed to preconcentrate and extract sulfonamides in fruit juices prior to high performance liquid chromatographic analysis . The DES was synthesized with trioctylmethylammonium chloride and 2 octanol at the molar ratio of 1 2 . Some parameters which affected the extraction efficiency were investigated and optimized including the volume of DES extraction method extraction time pH . Under the optimum conditions good linearity | A new eco friendly hydrophobic deep eutectic solvent DES was synthesized. The DES present excellent extraction efficiency for sulfonamides SAs . Hydrophobic DESs based on UA LLME combined with HPLC UVD method was developed. The method was applied in the determination of SAs from fruit juices. |
S0021967319309264 | When determining contaminants from environmental samples sample treatment plays an important role . Among the different extraction techniques available solid phase extraction has been commonly used for liquid samples as well as for solid samples after an extraction technique amenable for solids . The broad applicability of SPE is attributed to the availability of different sorbents . Among these sorbents the mixed mode ion exchange polymeric ones have been widely exploited since they suitably combine both capacity and selectivity . This review overviews the application of mixed mode ion exchange polymeric sorbents in environmental field when water and solid samples are analyzed . The sample analyzed the compounds determined the type of mixed mode sorbent selected the approach used and the SPE protocol applied are comprehensively discussed through different examples . This review intends to summarize the role of mixed mode ion exchange polymeric sorbents in the environmental field . | Mixed mode sorbents have been widely applied in the environmental field. They are used to both enrich contaminants and clean up interferences from complex samples. The optimization of the SPE protocol mainly in terms of pHs is important to establish ionic interactions. Different approaches single or combined cartridge can be explored to enhance their potential. |
S002196731930929X | Magnetic molecularly imprinted polymers combine nanotechnology and molecular imprinting technology to offer selective and tunable enrichment for water analysis . In this paper a selective sorbent was prepared by surface polymerization onto magnetic Fe | A pseudo template MMIP for PAHs was synthesized using RAFT polymerization. RAFT MMIP was used for dispersive solid phase extraction of PAHs from water. CCD and desirability function were used for simultaneous optimization of DSPE of 16 PAHs. MMIP DSPE showed excellent selectivity for adsorption of PAHs. MMIP DSPE was used for determination of PAHs in river water and produced water. |
S0021967319309306 | A device with four parallel channels was designed and manufactured by 3D printing in titanium . A simple experimental setup allowed splitting of the mobile phase in four parallel streams such that a single sample could be analysed four times simultaneously . The four capillary channels were filled with a monolithic stationary phase prepared using a zwitterionic functional monomer in combination with various dimethacrylate cross linkers . The resulting stationary phases were applicable in both reversed phase and hydrophilic interaction retention mechanisms . The mobile phase composition was optimized by means of a window diagram so as to obtain the highest possible resolution of dopamine precursors and metabolites on all columns . Miniaturized electrochemical detectors with carbon fibres as working electrodes and silver micro wires as reference electrodes were integrated in the device atthe end of each column . Experimental separations were successfully compared with those predicted by a three parameter retention model . Finally dopamine was determined in human urine to further confirm applicability of the developed device . | A device with four parallel channels was manufactured by 3D printing in titanium. A simple experimental setup allowed splitting of the mobile phase in parallel streams. Capillary channels were filled with a monolithic stationary phases. Miniaturized electrochemical detectors were integrated in the device. Dopamine was determined in human urine by using developed device. |
S0021967319309318 | Current metabolomics research utilizes liquid chromatography tandem mass spectrometry analyses to handle biological samples that contain thousands of quantifiable metabolites . However no LCMS MS condition is suitable for directly analyzing all metabolites . An alternative approach is to derivatize metabolites to impart desirable properties such as better chromatographic separation enhanced ionization efficiency or fluorescence detection . An important category of metabolites is amine containing compounds which includes amino acids neurotransmitters alkaloids biogenic amines etc . Various derivatization methods have been developed for amine groups but few studies have compared their relative strengths and weaknesses . We chose Dansyl Cl o phthalaldehyde Fmoc Cl Dabsyl Cl and Marfey s reagent to systematically compare their reactivity absorbance fluorescence chromatographic separation and ionization efficiencies under three pH conditions2.6 5.0 and 8.0 . Their MS MS fragmentation patterns were also examined under different collision energies . Overall Dansyl Cl is a very versatile derivatization method generating products with fluorescence and high ionization efficiency . Fmoc Cl is similarly useful under highly acidic chromatography conditions . Dabsyl Cl may be a good alternative at weakly acidic and weakly basic conditions . OPA is a versatile fluorogenic reagent and its chemistry may be fine tuned by incorporating different thiol molecules . Marfey s reagent is suboptimal in general but its chiral property is useful for the separation of enantiomers . All five were applied to the analyses of | Extensive cross comparisons conducted for Dansyl OPA Fmoc Dabsyl and Marfey s reagent. Elution pH in LCMS analysis greatly affects the performance of derivatization strategies. With. extract Dansyl labeling gives the greatest number identified compounds. With. extract each reagent yields a rather distinct compound coverage profile. No single reagent offers is clearly superior and case by case assessment is required. |
S002196731930932X | Our previous studies on protein adsorption to the anion exchangers of poly grafted Sepharose FF found that both adsorption capacity and uptake rate of bovine serum albumin increased greatly when the PEI grafting density reached over a critical ionic capacity due to the 3D protein binding and occurrence of chain delivery of bound proteins . Moreover by the investigation on the anion exchangers of diethylaminoethyl modified and DEAE dextran grafted Sepharose FF we found the unique role of surface ligand in facilitating protein uptake kinetics on dextran functionalized anion exchangers as the transfer station for the chain delivery of bound proteins . However what would be the contribution of surface ligands on the transport of bound proteins on PEI chains at a wide range across cIC particularly at the lower IC range where no chain delivery was present We have thus designed this research to answer the question . To this purpose we fabricated three series of PEI Sepharose FF resins one without surface ligand and two with surface DEAE modifications at DEAE coupling densities of 60 and 90mmol L and focused on the role of surface DEAE at different PEI densities in BSA adsorption equilibrium and uptake kinetics in a wide IC range of PEI across cIC . It was found that at low grafting ligand densities both adsorption capacity and uptake rate increased significantly after adding surface DEAE groups . At IC cIC however both adsorption capacity and uptake rate changed only slightly by the addition of surface DEAE groups . The results revealed that at IC cIC the surface DEAE groups provided the supplement of available binding sites and facilitated the happenings of the chain delivery of bound proteins as the transfer station both of which were limited at the low IC range . However at IC cIC the extended flexible PEI chains have already afforded 3D binding space with high accessibility and easy happening of chain delivery of bound proteins so the surface DEAE groups between neighboring PEI chains did not work in assisting the transport of bound proteins . Moreover when the IC was lower but close to the cIC the FF D PEI resins exhibited higher uptake rates than FF PEI resins at a similar or even lower IC values . These findings indicate that surface modification of charged groups in PEI based anion exchangers of low grafting density would be an efficient strategy to fabricate high performance protein ion exchangers . | DEAE groups are introduced to the gel surface of poly ethylenimine PEI Sepharose. Uptake capacity and rate increase with adding DEAE at PEI charge density 600mmol L. Capacity and rate change inappreciably with adding DEAE at charge density 600mmol L. DEAE PEI resin exhibits higher uptake rate than PEI resin at similar ionic capacity. |
S0021967319309331 | Over the past decade significant progress has been found in the upstream production processes shifting the main bottlenecks in current manufacturing platforms for biopharmaceuticals towards the downstream processing . Challenges in the purification process include reducing the production costs developing robust and efficient purification processes as well as integrating both upstream and downstream processes . Microfluidic technologies have recently emerged as effective tools for expediting bioprocess design in a cost effective manner since a large number of variables can be evaluated in a small time frame using reduced volumes and manpower . Their modularity also allows to integrate different unit operations into a single chip and consequently to evaluate the effect of each stage on the overall process efficiency . | Rapid and low cost method to evaluate lysis efficiency of different solutions. Simple microscale optimization of a continuous and modular downstream process. Higher than 90 lysis efficiencies obtained for different solutions and conditions. Integrable with other microfluidic modules mimicking different unitary operations. |
S0021967319309380 | Estimation of the properties of mesoporous aluminosilicates in various environments is important when assessing their sorption capacity . Using inverse liquid chromatography Hansen solubility parameters and linear free energy relationship parameters were calculated to determine the properties of aluminosilicates in a protic and an aprotic system using water and acetonitrile as the mobile phase respectively . The calculated Hansen parameters reflecting the ability of the material under investigation to different types of intermolecular interactions slightly differ depending on the mobile phase used . It was found that in the presence of water the surface of aluminosilicates shows a weaker ability to interact as evidenced by negative or near zero | Surface properties of aluminosilicates can be estimate using liquid chromatography. The nature of the solvent affects the surface properties of aluminosilicates. Water reduces ability of the aluminosilicates surface to interactions. |
S0021967319309392 | The facile enrichment of glycopeptides or glycoproteins poses great challenges for glycoproteomic research . In this study a novel hydrophilic material named zwitterionic hydrophilic L cysteine derivatized straticulate C | A zwitterionic hydrophilic L Cysteine derivatized straticulate C. composites were synthesized. The materials show high selectivity low detection limit high enrichment efficiency and high recovery rate for N glycopeptides. Up to 1809 N glycopeptides and 876 N glycoproteins could be enriched from mililiters of human urine samples. |
S0021967319309410 | In this study a reliable and novel coupling of pipette tip micro solid phase extraction with corona discharge ionization ion mobility spectrometry was developed for on site fast detection of benzodiazepines in dietary supplements . The poly monoliths fabricated in pipette tips through an in situ polycondensation reaction . The extraction procedure of PT SPE for aqueous sample was performed for an appropriate number of aspirating dispensing cycles by using a manual micropipettor . Then analytes retained in the polymeric monoliths were eluted with elution solvents by repeating the aspirating dispensing cycles and the eluates were analyzed by CD IMS . In order to find the best extraction conditions several parameters such as the number of aspirating dispensing cycles for extraction and desorption pH elution solvent amount of polymer and ionic strength were investigated . Under the optimal conditions the LOD of this method was in the range of 515ngmL | PT SPE was coupled with CD IMS for the first time. In tip poly St DVB monolith was used for extraction BZDs in dietary supplements. High throughput sampling can be achieved by using multichannel pipettor. The method has potential for on site environmental and public security monitoring. |
S0021967319309422 | The analysis of heparan sulfate disaccharides poses a real challenge both from chromatographic and mass spectrometric point of view . This necessitates the constant improvement of their analytical methodology . In the present study the chromatographic effects of solvent composition salt concentration and salt type were systematically investigated in isocratic HILIC WAX separations of heparan sulfate disaccharides . The combined use of 75 acetonitrile with ammonium formate had overall benefits regarding intensity detection limits and peak shape for all salt concentrations investigated . Results obtained with the isocratic measurements suggested the potential use of a salt gradient method in order to maximize separation efficiency . A 3 step gradient from 14mM to 65mM ammonium formate concentration proved to be ideal for separation and quantitation . The LOD of the resulting method was 0.81.5fmol for the individual disaccharides and the LOQ was between 2.55fmol . Outstanding linearity could be observed up to 2 pmol . This novel combination provided sufficient sensitivity for disaccharide analysis which was demonstrated by the analysis of heparan sulfate samples from porcine and bovine origin . | Separation of heparan sulfate disaccharides using self packed HILIC WAX columns. Detailed mapping of solvent composition and salt concentration effects. Different elution behavior for various HS disaccharides in HILIC WAX. Wide linearity range with ammonium formate gradient method 2.5fmol2pmol . Sulfation pattern can be distinguished between samples of different biological origin. |
S0021967319309434 | The advent of supercritical fluid chromatography in the 90s has changed preparative liquid chromatography . SFC is an improved way for separating chiral compounds during drug discovery processes yielding upwards of one hundred grams of pure enantiomers or during clinical trials requiring higher quantities . | Propranolol is separated by SFC on Chiralpak AD H. Four columns of different dimension were used. Column dimension impacts production rate and productivity. Column dimension does impact solvent use and E Factor. The utilization of the shortest column leads to the highest productivity. |
S0021967319309446 | As short chain chlorinated paraffins are listed on several monitoring programs validated methods are essential . However their complexity and the lack of commercially available certified reference materials hinder a proper validation of methods . Instead one method is usually validated by evaluating performances and results of spiked materials with that of one other method which could easily lead to unreliable results . | SCCPs were determined in candidate reference materials for potential certification. Determination involved four methods with different principles. The suitability of the GCECNILRMS method for SCCP determination is doubtful. Using spiked samples or solutions might not always be ideal for method validation. The results provide a good basis for possible certification of one of the materials. |
S002196731930946X | In this work the Dubsky s model proposed for Capillary Electrophoresis enantioseparation systems with a mixture of chiral selectors was applied to the rapid optimization of the simultaneous enantiomeric separation of a multicomponent mixture of six phenoxy acid herbicides using a dual system of two cyclodextrins CD and heptakis CD . Simply by carrying out a small number of individual experiments separately with each CD the Dubsky s model enabled to foresee the results that could be obtained for any possible combination of concentrations and relative proportion of both CDs in the mixture . Results obtained in this work demonstrated that the model was successful by improving the previous results experimentally obtained by the trial and error method for the simultaneous enantiomeric separation of the six phenoxy acid herbicides studied in this work . In fact the separation was improved in terms of enantiomeric resolutions obtained and by considerably reducing the time to optimize the separation conditions enabling to find in a faster and efficient way the most adequate proportion of both CDs and the concentration of each CD in the mixture to obtain baseline separation of the twelve enantiomers . Additionally the apparent complexation constants between enantiomers and each CD were calculated . This is the first time that the above mentioned model was applied to a multicomponent mixture of chiral compounds . | Dubsky s etal. model for CE enantioseparations with dual systems was applied. Modeling based optimization of chiral separation of multicomponent mixtures. Quick optimization of simultaneous chiral separation of phenoxy acid herbicides. Improved resolution between enantiomers and among consecutive compounds. Fast and efficient optimization against trial and error procedure. |
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