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Qiqin Wang - One of the best experts on this subject based on the ideXlab platform.
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determination of l norvaline and l tryptophan in dietary supplements by nano lc using an o 2 methacryloyloxy ethylcarbamoyl 10 11 Dihydroquinidine silica hybrid monolithic column
Journal of Pharmaceutical Analysis, 2020Co-Authors: Elena Sanchezlopez, Qiqin Wang, Zhengjin Jiang, Maria Luisa MarinaAbstract:Abstract An analytical methodology based on an O-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-Dihydroquinidine (MQD)-silica hybrid monolithic column was developed for the enantioseparation of 9-fluorenylmethoxycarbonyl (FMOC) derivatized amino acids by nano-liquid chromatography. The mobile phase was optimized including the apparent pH, content of ACN, and concentration of the buffer to obtain a satisfactory enantioresolution performance. 27 FMOC derivatized amino acids including 19 protein and 8 non-protein amino acids were tested, and 19 out of them were enantiomerically discriminated obtaining baseline separation for 11 of them. Analytical characteristics of the method were evaluated for norvaline and tryptophan in terms of linearity, precision, accuracy, limits of detection (LOD) and quantitation (LOQ) showing good performance to be applied to the enantiomeric determination of these amino acids in dietary supplements. LOD and LOQ values were 9.3 and 31 μM for norvaline enantiomers and 7.5 and 25 μM for tryptophan enantiomers, respectively. The contents of d -norvaline and d -tryptophan were below their respective LODs in all the analyzed samples. Quantitation of l -tryptophan and l -norvaline showed good agreement with the labeled contents except for one sample which did not show presence of l -norvaline, contrary to the label indication.
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preparation of an o 2 methacryloyloxy ethylcarbamoyl 10 11 Dihydroquinidine silica hybrid monolithic column for the enantioseparation of amino acids by nano liquid chromatography
Journal of Chromatography A, 2019Co-Authors: Qiqin Wang, Zhengjin Jiang, Elena Sanchezlopez, Maria Luisa MarinaAbstract:An O-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-Dihydroquinidine (MQD)-silica hybrid monolithic column was prepared by a facile "one-step" strategy within a 100 μm I.D. capillary. The influence of the methanol, ethylene glycol and water volume ratio, reaction temperature and time, cetyltrimethylammonium bromide and MQD monomers content and volume ratio of tetramethoxysilane and vinyltrimethoxysilane was investigated to obtain a satisfactory morphology of monolithic columns. The optimized MQD-silica hybrid monolithic column was evaluated in terms of permeability, stability, efficiency, reproducibility, and was characterized by scanning electron microscopy and nano-liquid chromatography. Among the 52 N-derivatized protein and non-protein amino acids, a total of 44 analytes could be baseline enantioseparated using the optimized conditions in either reversed phase mode (RPM) or polar organic phase mode (POM). The results showed that POM (ACN/MeOH/HAc/TEA (60/40/0.055/0.005, v/v/v/v)) offered better performance than RPM (10 mM ammonium acetate/ACN (30/70, v/v) (apparent pH=5.3)) in terms of enantioresolution and efficiency with shorter analysis times.
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enantioseparation of n derivatized amino acids by micro liquid chromatography using carbamoylated quinidine functionalized monolithic stationary phase
Journal of Chromatography A, 2014Co-Authors: Qiqin Wang, Jun Feng, Hai Han, Peijie Zhu, Maria Luisa Marina, Jacques Crommen, Zhengjin JiangAbstract:In order to obtain satisfactory column permeability, efficiency and selectivity for micro-HPLC, a capillary monolithic column containing O-9-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-Dihydroquinidine (MQD) as chiral selector was re-optimized. The monolithic column was used to successfully enantioresolve a wide range of N-derivatized amino acids including alanine, leucine, methionine, threonine, phenylalanine, valine, serine, isoleucine, tryptophan, and cysteine. The influence of mobile phase parameters, such as the organic solvent type and concentration, the apparent pH, and buffer concentration, on retention and enantioseparation of N-derivatized amino acids has been investigated. 3,5-dinitrobenzoyl-amino acids and 3,5-dichlorobenzoyl-amino acids were resolved into enantiomers with exceptionally high selectivity and resolution. The chemoselectivity of the monolithic column for a multicomponent mixture of N-derivatized amino acids was also investigated. A mixture of three pairs of 3,5-dichlorobenzoyl-amino acids could be fully resolved in 22.5 min.
Maria Luisa Marina - One of the best experts on this subject based on the ideXlab platform.
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determination of l norvaline and l tryptophan in dietary supplements by nano lc using an o 2 methacryloyloxy ethylcarbamoyl 10 11 Dihydroquinidine silica hybrid monolithic column
Journal of Pharmaceutical Analysis, 2020Co-Authors: Elena Sanchezlopez, Qiqin Wang, Zhengjin Jiang, Maria Luisa MarinaAbstract:Abstract An analytical methodology based on an O-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-Dihydroquinidine (MQD)-silica hybrid monolithic column was developed for the enantioseparation of 9-fluorenylmethoxycarbonyl (FMOC) derivatized amino acids by nano-liquid chromatography. The mobile phase was optimized including the apparent pH, content of ACN, and concentration of the buffer to obtain a satisfactory enantioresolution performance. 27 FMOC derivatized amino acids including 19 protein and 8 non-protein amino acids were tested, and 19 out of them were enantiomerically discriminated obtaining baseline separation for 11 of them. Analytical characteristics of the method were evaluated for norvaline and tryptophan in terms of linearity, precision, accuracy, limits of detection (LOD) and quantitation (LOQ) showing good performance to be applied to the enantiomeric determination of these amino acids in dietary supplements. LOD and LOQ values were 9.3 and 31 μM for norvaline enantiomers and 7.5 and 25 μM for tryptophan enantiomers, respectively. The contents of d -norvaline and d -tryptophan were below their respective LODs in all the analyzed samples. Quantitation of l -tryptophan and l -norvaline showed good agreement with the labeled contents except for one sample which did not show presence of l -norvaline, contrary to the label indication.
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preparation of an o 2 methacryloyloxy ethylcarbamoyl 10 11 Dihydroquinidine silica hybrid monolithic column for the enantioseparation of amino acids by nano liquid chromatography
Journal of Chromatography A, 2019Co-Authors: Qiqin Wang, Zhengjin Jiang, Elena Sanchezlopez, Maria Luisa MarinaAbstract:An O-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-Dihydroquinidine (MQD)-silica hybrid monolithic column was prepared by a facile "one-step" strategy within a 100 μm I.D. capillary. The influence of the methanol, ethylene glycol and water volume ratio, reaction temperature and time, cetyltrimethylammonium bromide and MQD monomers content and volume ratio of tetramethoxysilane and vinyltrimethoxysilane was investigated to obtain a satisfactory morphology of monolithic columns. The optimized MQD-silica hybrid monolithic column was evaluated in terms of permeability, stability, efficiency, reproducibility, and was characterized by scanning electron microscopy and nano-liquid chromatography. Among the 52 N-derivatized protein and non-protein amino acids, a total of 44 analytes could be baseline enantioseparated using the optimized conditions in either reversed phase mode (RPM) or polar organic phase mode (POM). The results showed that POM (ACN/MeOH/HAc/TEA (60/40/0.055/0.005, v/v/v/v)) offered better performance than RPM (10 mM ammonium acetate/ACN (30/70, v/v) (apparent pH=5.3)) in terms of enantioresolution and efficiency with shorter analysis times.
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enantioseparation of n derivatized amino acids by micro liquid chromatography using carbamoylated quinidine functionalized monolithic stationary phase
Journal of Chromatography A, 2014Co-Authors: Qiqin Wang, Jun Feng, Hai Han, Peijie Zhu, Maria Luisa Marina, Jacques Crommen, Zhengjin JiangAbstract:In order to obtain satisfactory column permeability, efficiency and selectivity for micro-HPLC, a capillary monolithic column containing O-9-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-Dihydroquinidine (MQD) as chiral selector was re-optimized. The monolithic column was used to successfully enantioresolve a wide range of N-derivatized amino acids including alanine, leucine, methionine, threonine, phenylalanine, valine, serine, isoleucine, tryptophan, and cysteine. The influence of mobile phase parameters, such as the organic solvent type and concentration, the apparent pH, and buffer concentration, on retention and enantioseparation of N-derivatized amino acids has been investigated. 3,5-dinitrobenzoyl-amino acids and 3,5-dichlorobenzoyl-amino acids were resolved into enantiomers with exceptionally high selectivity and resolution. The chemoselectivity of the monolithic column for a multicomponent mixture of N-derivatized amino acids was also investigated. A mixture of three pairs of 3,5-dichlorobenzoyl-amino acids could be fully resolved in 22.5 min.
Zhengjin Jiang - One of the best experts on this subject based on the ideXlab platform.
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determination of l norvaline and l tryptophan in dietary supplements by nano lc using an o 2 methacryloyloxy ethylcarbamoyl 10 11 Dihydroquinidine silica hybrid monolithic column
Journal of Pharmaceutical Analysis, 2020Co-Authors: Elena Sanchezlopez, Qiqin Wang, Zhengjin Jiang, Maria Luisa MarinaAbstract:Abstract An analytical methodology based on an O-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-Dihydroquinidine (MQD)-silica hybrid monolithic column was developed for the enantioseparation of 9-fluorenylmethoxycarbonyl (FMOC) derivatized amino acids by nano-liquid chromatography. The mobile phase was optimized including the apparent pH, content of ACN, and concentration of the buffer to obtain a satisfactory enantioresolution performance. 27 FMOC derivatized amino acids including 19 protein and 8 non-protein amino acids were tested, and 19 out of them were enantiomerically discriminated obtaining baseline separation for 11 of them. Analytical characteristics of the method were evaluated for norvaline and tryptophan in terms of linearity, precision, accuracy, limits of detection (LOD) and quantitation (LOQ) showing good performance to be applied to the enantiomeric determination of these amino acids in dietary supplements. LOD and LOQ values were 9.3 and 31 μM for norvaline enantiomers and 7.5 and 25 μM for tryptophan enantiomers, respectively. The contents of d -norvaline and d -tryptophan were below their respective LODs in all the analyzed samples. Quantitation of l -tryptophan and l -norvaline showed good agreement with the labeled contents except for one sample which did not show presence of l -norvaline, contrary to the label indication.
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preparation of an o 2 methacryloyloxy ethylcarbamoyl 10 11 Dihydroquinidine silica hybrid monolithic column for the enantioseparation of amino acids by nano liquid chromatography
Journal of Chromatography A, 2019Co-Authors: Qiqin Wang, Zhengjin Jiang, Elena Sanchezlopez, Maria Luisa MarinaAbstract:An O-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-Dihydroquinidine (MQD)-silica hybrid monolithic column was prepared by a facile "one-step" strategy within a 100 μm I.D. capillary. The influence of the methanol, ethylene glycol and water volume ratio, reaction temperature and time, cetyltrimethylammonium bromide and MQD monomers content and volume ratio of tetramethoxysilane and vinyltrimethoxysilane was investigated to obtain a satisfactory morphology of monolithic columns. The optimized MQD-silica hybrid monolithic column was evaluated in terms of permeability, stability, efficiency, reproducibility, and was characterized by scanning electron microscopy and nano-liquid chromatography. Among the 52 N-derivatized protein and non-protein amino acids, a total of 44 analytes could be baseline enantioseparated using the optimized conditions in either reversed phase mode (RPM) or polar organic phase mode (POM). The results showed that POM (ACN/MeOH/HAc/TEA (60/40/0.055/0.005, v/v/v/v)) offered better performance than RPM (10 mM ammonium acetate/ACN (30/70, v/v) (apparent pH=5.3)) in terms of enantioresolution and efficiency with shorter analysis times.
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enantioseparation of n derivatized amino acids by micro liquid chromatography using carbamoylated quinidine functionalized monolithic stationary phase
Journal of Chromatography A, 2014Co-Authors: Qiqin Wang, Jun Feng, Hai Han, Peijie Zhu, Maria Luisa Marina, Jacques Crommen, Zhengjin JiangAbstract:In order to obtain satisfactory column permeability, efficiency and selectivity for micro-HPLC, a capillary monolithic column containing O-9-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-Dihydroquinidine (MQD) as chiral selector was re-optimized. The monolithic column was used to successfully enantioresolve a wide range of N-derivatized amino acids including alanine, leucine, methionine, threonine, phenylalanine, valine, serine, isoleucine, tryptophan, and cysteine. The influence of mobile phase parameters, such as the organic solvent type and concentration, the apparent pH, and buffer concentration, on retention and enantioseparation of N-derivatized amino acids has been investigated. 3,5-dinitrobenzoyl-amino acids and 3,5-dichlorobenzoyl-amino acids were resolved into enantiomers with exceptionally high selectivity and resolution. The chemoselectivity of the monolithic column for a multicomponent mixture of N-derivatized amino acids was also investigated. A mixture of three pairs of 3,5-dichlorobenzoyl-amino acids could be fully resolved in 22.5 min.
Wolfgang Lindner - One of the best experts on this subject based on the ideXlab platform.
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chiral monolithic columns for enantioselective capillary electrochromatography prepared by copolymerization of a monomer with quinidine functionality 1 optimization of polymerization conditions porous properties and chemistry of the stationary phase
Analytical Chemistry, 2000Co-Authors: Michael Lammerhofer, Eric C Peters, And Frantisek Svec, Jean M J Frechet, Wolfgang LindnerAbstract:Monolithic columns for chiral capillary electrochromatography have been prepared within the confines of untreated fused-silica capillaries in a single step by a simple copolymerization of mixtures of O-[2-(methacryloyloxy)ethylcarbamoyl]-10,11-Dihydroquinidine, ethylene dimethacrylate, and glycidyl methacrylate or 2-hydroxyethyl methacrylate in the presence of mixture of cyclohexanol and 1-dodecanol as a porogenic solvent. The porous properties of the monolithic columns can easily be controlled through changes in the composition of the binary porogenic solvent. Although both thermal- and UV light-initiated polymerizations afford useful capillary columns, monoliths prepared using the former approach exhibit better chromatographic properties. The ability to control pore size independently of the polymerization mixture composition enables the preparation of monoliths with varying percentages of the chiral monomer and cross-linker, as well as the optimization of their separation properties. Very good separati...
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chiral monolithic columns for enantioselective capillary electrochromatography prepared by copolymerization of a monomer with quinidine functionality 2 effect of chromatographic conditions on the chiral separations
Analytical Chemistry, 2000Co-Authors: Michael Lammerhofer, And Frantisek Svec, Jean M J Frechet, Wolfgang LindnerAbstract:The effect of chromatographic conditions on the performance of chiral monolithic poly(O-[2-(methacryloyloxy)ethylcarbamoyl]-10,11-Dihydroquinidine-co-ethylene dimethacrylate-co-2-hydroxyethyl methacrylate) columns in the capillary electrochromatography of enantiomers has been studied. The flow velocity was found to be proportional to the pore size of the monolith and both the pH and the composition of the mobile phase. The length of both open and monolithic segments of the capillary column was found to exert a substantial effect on the run times. The use of monoliths as short as 8.5 cm and the “short-end” injection technique enabled the separations to be achieved in ∼5 min despite the high retentitivity of the quinidine selector. Very high column efficiencies of close to 250 000 plates/m and good selectivities were achieved for the separations of numerous enantiomers using the chiral monolithic capillaries with the optimized chromatographic conditions.
Vahideh Zadsirjan - One of the best experts on this subject based on the ideXlab platform.
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application of asymmetric sharpless aminohydroxylation in total synthesis of natural products and some synthetic complex bio active molecules
RSC Advances, 2018Co-Authors: Majid M Heravi, Tahmineh Baie Lashaki, Bahareh Fattahi, Vahideh ZadsirjanAbstract:This report illustrates the applications of Asymmetric Sharpless Aminohydroxylation (ASAH) in the stereoselective synthesis of vicinal amino alcohols as important intermediates in the total synthesis of complex molecules and natural products with significant biological activities. The ASHA allows the regio- syn-selective synthesis of 1,2-amino alcohols via reaction of alkenes with salts of N-halosulfonamides, -amides and -carbamates employing osmium tetroxide (OsO4) as an efficient catalyst. In this reaction, chirality is induced via the addition of dihydroquinine- and Dihydroquinidine as derived chiral ligands.