Single-walled carbon nanotubes(SWNTs) have a high adsorption ability and nanoscale interactions. Cellulose trisphenylcarbamates possess high enantioseparation ability in high-performance liquid chromatography(HPLC...Single-walled carbon nanotubes(SWNTs) have a high adsorption ability and nanoscale interactions. Cellulose trisphenylcarbamates possess high enantioseparation ability in high-performance liquid chromatography(HPLC). Single-walled carbon nanotubes mixed with cellulose trisphenylcarbamate are coated on the silica gel as chiral stationary phases and higher enantioseparation factors are obtained. After a single-walled carbon nanotube is linked to the 6-pesition of cellulose 2,3-bisphenylcarbamate, its enantioseparation resolution increases compared to that of the cellulose trisphenylcarbamate. It is the first time that SWNTs have been applied to enantioseparation. The results indicate that the single-walled carbon nanotubes are good promoters of chiral recognition. This method can be used to improve the enantioseparation efficiency of the polysaccharide chiral stationary phases.展开更多
The enantiomers separation of thirteen drugs collected in Ch.P2010 was performed on chiral stationary phase of cellulose ramification (chiralpak OD and chiralpak OJ) by high performance liquid chromatographic (HPLC) m...The enantiomers separation of thirteen drugs collected in Ch.P2010 was performed on chiral stationary phase of cellulose ramification (chiralpak OD and chiralpak OJ) by high performance liquid chromatographic (HPLC) methods, which included ibuprofen (C1), ketoprofen (C2), nitrendipine (C3), nimodipine (C4), felodipine (C5), omeprazole (C6), praziquantel (C7), propranolol hydrochloride (C8), atenolol (C9), sulpiride (C10), clenbuterol hydrochloride (C11), verapamil hydrochloride (C12), and chlorphenamine maleate (C13). The mobile phase consisted of isopropanol and n-hexane. The detection wavelength was set at 254 nm and the fiow rate was 0.7 mL/min. The enantiomers separation of these thirteen racemates on chiralpak OD column and chiralpak OJ column was studied, while the effects of proportion of organic additives, alcohol displacer and temperature on the separation were studied. And the mechanism of some of racemates was discussed. The results indicated that thirteen chiral drugs could be separated onchiral stationary phase of cellulose ramification in normal phase chromatographic system. The chromatographic retention and resolution of enantiomers could be adjusted by factors including column temperature and the concentration of alcohol displacer and organic alkaline modifier in mobile phase. It was shown that the resolution was improved with reducing concentration of alcohol displacer. When concentration of organic alkaline modifier was 0.2% (v/v), the resolution and the peak shape were fairly good. Most racemates mentioned above had better resolution at column temperature of 25 1C. When racemates were separated, the temperature should be kept so as to obtain stable separation results.展开更多
This paper presents the enantioseparation using glucose, cellobiose, lactose and raffinose as chiral selector bonded to silica gel via an arm in HPLC. Surprisingly, they also possess high enantioseparation selectivity...This paper presents the enantioseparation using glucose, cellobiose, lactose and raffinose as chiral selector bonded to silica gel via an arm in HPLC. Surprisingly, they also possess high enantioseparation selectivity, may be used in normal-phase and reversed- phase mode, and there is a big chiral discriminating complementary. This work indicates that oligosaccharides could soon become very attractive as a new class of chiral stationary phase for HPLC.展开更多
Three novel chiral selectors 4a-c were synthesized from (S)-amino acids and (R)-1-phenyl-2-(4-methylphenyl)ethylamine. 4a-c were connected to 3-aminopropylsilanized silica gel to be used as the chiral stationary...Three novel chiral selectors 4a-c were synthesized from (S)-amino acids and (R)-1-phenyl-2-(4-methylphenyl)ethylamine. 4a-c were connected to 3-aminopropylsilanized silica gel to be used as the chiral stationary phase for HPLC. Five amino acid derivatives and two pyrethroid insecticides were fairly resolved on these three new chiral stationary phases under normal phase condition.展开更多
Three new hybrid organic/inorganic polymeric ligand-exchange chiral stationary phases were developed by radical chain transfer reaction and surface grafting on silica gel, and successfully used for the enantioseparati...Three new hybrid organic/inorganic polymeric ligand-exchange chiral stationary phases were developed by radical chain transfer reaction and surface grafting on silica gel, and successfully used for the enantioseparations of DL-amino acids and DL-hydroxyl adds. The resolutions were achieved by using water containing 2.0 × 10^-4 mol/L of CuAc2 as a mobile phase, column temperature of 40 ℃, flow rate of 1.0 mL/min and detection at UV 254 nm. The elution order of D-isomer before L-isomer was observed for all DL-amino acids resolved except DL-Pro.展开更多
Two polyurethanes of different molecular weights were prepared by the copolymerization of phenyl diisocyanate and diisopropyl tartrate. The polyurethanes having terminal isocyanate groups were reacted with 3-aminoprop...Two polyurethanes of different molecular weights were prepared by the copolymerization of phenyl diisocyanate and diisopropyl tartrate. The polyurethanes having terminal isocyanate groups were reacted with 3-aminopropyl silica gel to afford two chiral stationary phases. The M^- n of the two polyurethanes were 4057 g/mol and 6442 g/mol. The polyurethanes and the corresponding chiral stationary phases were characterized by FT-IR,^1 H NMR and elemental analysis. The loading capacities of the polyurethanes on silica gel were 0.68 mmol units/g and 0.61 mmol units/g, respectively. The separation performance and the influence of additives, triethylamine and trichloroacetic acid, on the separation of chiral compounds were investigated by HPLC. The chiral stationary phase prepared from polyurethane with M^- n of 4057 g/mol demonstrated better enantioseparation capability than that with M^- n of 6442 g/mol. Additionally, it was found that the addition of triethylamine and trichloroacetic acid in the mobile phases significantly improved the enantioseparation for these two chiral stationary phases.展开更多
A novel chiral stationary phase (CSP) was prepared by immobilizing mono(6A-N-1-(2-hydroxyl)-phenylethylimino-6A- deoxy)-β-cyclodextrin onto the surface of silica gel via a longer spacer. This chiral stationary ...A novel chiral stationary phase (CSP) was prepared by immobilizing mono(6A-N-1-(2-hydroxyl)-phenylethylimino-6A- deoxy)-β-cyclodextrin onto the surface of silica gel via a longer spacer. This chiral stationary phase exhibited good enantioselectivity for a variety of chiral compounds under reversed-phase conditions.展开更多
Amylose tris (phenylcarbamate) chiral stationary phase (ATPC-CSP) was prepared and used for optical resolution of clusters 1 and 2. n-Hexane/2-propanol ( 99/1; v/v) were found to be the most suitable mobile phase on ...Amylose tris (phenylcarbamate) chiral stationary phase (ATPC-CSP) was prepared and used for optical resolution of clusters 1 and 2. n-Hexane/2-propanol ( 99/1; v/v) were found to be the most suitable mobile phase on ATPC-CSP.展开更多
Three chiral stationary phases(CSPl, CSP2 and CSP3) for ligand-exchange chromatography were prepared by firstly using dimethylchlorosilane as an endcapping reagent for decreasing residual silanol groups on the surfa...Three chiral stationary phases(CSPl, CSP2 and CSP3) for ligand-exchange chromatography were prepared by firstly using dimethylchlorosilane as an endcapping reagent for decreasing residual silanol groups on the surface of silica gel, and then modifying the surface of silica gel with allyl glycidyl ether and alkenes through the hydrosilation reaction, and lastly introducing L-proline as a chiral selector. The enantiomer resolutions of 14 amino acids and 2 hydroxyl acids were completed on the CSPs by using an aqueous solution of Cu(Ac)2 as mobile phase at a flow rate of 1.0 mL/min and column temperature of 40 ℃ with detection at UV 254 nm. In terms of enantioseleetivity a, column efficiency and resolution Rs, the chromatographic behaviors of the analytes on the CSPs were discussed via comparing them to those on the CSP4 prepared via the reference method. The results show that enantioselectivity a, column efficiency and resolution Rs of the analytes on the CSPs could be improved by using the above modifying method.展开更多
Click chemistry was applied to immobilize L-proline derivative onto azide-modified silica gel to give a novel chiral stationary phase (denoted as click-CSP) for ligand exchange chromatography. The developed protocol...Click chemistry was applied to immobilize L-proline derivative onto azide-modified silica gel to give a novel chiral stationary phase (denoted as click-CSP) for ligand exchange chromatography. The developed protocol combines the benefits of operational simplicity, exceptionally mild conditions and high surface loadings. The enantioselectivity α of some DL-arnino acids on the click- CSP were found to be in the range from 1.13 to 3.46. The chromatographic resolutions of some DL-amino acids and the stability study firmly illustrate the potential of click chemistry for preparation chiral stationary phase for ligand exchange chromatography.展开更多
A new type of molecular imprinting stationary phase was prepared by using R- (+)-α -methylbenzy lamine as the print molecule. Experiments of high performance liquid chromatography show that the new stationary phase h...A new type of molecular imprinting stationary phase was prepared by using R- (+)-α -methylbenzy lamine as the print molecule. Experiments of high performance liquid chromatography show that the new stationary phase has high enantio-selectivity and discriminates (R, S) -(± )- α -methylbenzylamine successful ly with α value of 1. 67展开更多
A novel chiral stationary phase (CSP1) for ligand-exchange chromatography (CLEC) was prepared by firstly using dimethylchlorosilane as an endcapping reagent for decreasing residual silanol group on the surface of ...A novel chiral stationary phase (CSP1) for ligand-exchange chromatography (CLEC) was prepared by firstly using dimethylchlorosilane as an endcapping reagent for decreasing residual silanol group on the surface of silica gel, and then introducing L-Pro as a chiral selector and hydrophobic octyl group to the silica gel surface simultaneously. The enantioseparations of 14 DL-amino acids on CSP1 were achieved with the enantioselectivity α ranging from 1.09 to 2.44 and the resolution Rs being between 0.8 and 6.3. The chromatographic performances of CSP1 with the bonded phase (CSP2) prepared using reference method were compared. The results showed that the column efficiency and resolution Rs of chiral stationary phase could be improved by using the above modifying method.展开更多
Several kinds of racemic naproxen ester were successfully separated on CTMB chiral stationary phase with hexane-ethanol (98:2, vol./vol.) as the mobile phase. The influence of mobile phase composition and structure o...Several kinds of racemic naproxen ester were successfully separated on CTMB chiral stationary phase with hexane-ethanol (98:2, vol./vol.) as the mobile phase. The influence of mobile phase composition and structure of racemic naproxen ester on chiral separation was studied and the chiral recognition mechanism of CTMB was discussed.展开更多
Excellent resolution of racemic 2-phenyl-1,1-cyclopropanedicarbonitrile and its nine analogues was accomplished using 100-5CH1-TBB chiral stationary phase under normal-phase HPLC conditions. The influence of mobile ph...Excellent resolution of racemic 2-phenyl-1,1-cyclopropanedicarbonitrile and its nine analogues was accomplished using 100-5CH1-TBB chiral stationary phase under normal-phase HPLC conditions. The influence of mobile phase and the optimum conditions for the resolution of optically active enantiomers were investigated.展开更多
The enantiomers separation of ei ght pharmaceutical racemates collected in Chinese Pharmacopoeia 2010(Ch.P2010),including nitrendipine,felodipine,omeprazole,praziquantel,sulpiride,clenbuterol hydrochloride,verapamil h...The enantiomers separation of ei ght pharmaceutical racemates collected in Chinese Pharmacopoeia 2010(Ch.P2010),including nitrendipine,felodipine,omeprazole,praziquantel,sulpiride,clenbuterol hydrochloride,verapamil hydrochloride and chlorphenamine maleate,was performed on chiral stationary phase of amylose ramification by high performance liquid chromatography(HPLC)on Chiralpak AD-H column and Chiralpak AS-H column with the mobile phase consisted of isopropanol and n-hexane.The detection wavelength and the flow rate were set at 254 nm and 0.7 mL/min,respectively.The effects of proportion of organic additives,alcohol displacer and temperature on the separation were investigated.The results indicated that eight chiral drugs were separated on chiral stationary phase of amylase ramification in normal phase chroma tographic system.The chromatographic retention and resolution of enantiomers were adjusted by factors,including the changes of the concentration of alcohol displacer in mobile phase,organic alkaline modifier and column temperature.It was shown that the resolution was improved with reducing concentration of alcohol displacer.When the concentration of organic alkaline modifier was 0.2%,the resolution and the peak shape were fairly good.Most racemates mentioned above had the best resolution at column temperature of 25℃.The best temperature should be kept unchanged in the process of separation so as to obtain stable separation results.展开更多
Cellulose tris(4-methylphenylcarbamate), amylosetris(3,5-di-methylphenylcarbamate) and amylose tris (phenylcarbamate) were prepared by the methodreported by Okamoto and were coated onto an aminopropylated mesoporous s...Cellulose tris(4-methylphenylcarbamate), amylosetris(3,5-di-methylphenylcarbamate) and amylose tris (phenylcarbamate) were prepared by the methodreported by Okamoto and were coated onto an aminopropylated mesoporous spherical silica gel. Thesefinal products were used as chiral stationary phases of high performance liquid chromatography forthe eighteen structurally related biphenyl compounds. The resolution was made using normal-phasemethodology with a mobile phase consisting of n-hexane-alcohol (ethanol, 1-propanol, 2-pro-panol or1-butanol). The effects of various aliphatic alcohols in the mobile phase were studied. Thestructural features of the solutes that influence then- k′ were discussed. A dominant effect oftrifluoroacetic acid on chiral separation of acidic solutes was noted.展开更多
Chiral covalent organic frameworks(CCOFs) featuring chirality, stability, and good porosity have attracted a considerable amount of attention due to their important applications, such as asymmetric catalysis, chiral s...Chiral covalent organic frameworks(CCOFs) featuring chirality, stability, and good porosity have attracted a considerable amount of attention due to their important applications, such as asymmetric catalysis, chiral separation, and chiral recognition. In this study, a β-cyclodextrin(β-CD) covalent organic framework(β-CD-COF) diluted with polysiloxane OV-1701 was explored as a novel chiral stationary phase(CSP) for gas chromatography(GC) separation of racemates. The β-CD-COF coated capillary column had excellent selectivity, not only for the separation of linear alkanes, linear alcohols, fatty acid methyl esters mixture, the Grob mixture and positional isomers, but also for the resolution of chiral compounds, including chiral alcohols, aldehydes, ethers, and amino acid derivatives. In addition, the β-CD-COF-coated capillary column presented good repeatability and reproducibility. This work indicated the great potential of the CCOFs coated capillary column for the chromatographic separation of enantiomers.展开更多
A new method to prepare polysaccharide-coating type chiral stationary phases (CSPs) was developed in this work. As a typical example, naked silica gel was coated by cellulose, which was then derivatized with 3,5-dim...A new method to prepare polysaccharide-coating type chiral stationary phases (CSPs) was developed in this work. As a typical example, naked silica gel was coated by cellulose, which was then derivatized with 3,5-dimethylbenzoyl chloride to afford cellulose tris(3,5-dimethylbenzoate)-silica gel (CTDBS) complex. The silanols on CTDBS were end-capped with 3- aminopropyltriethoxysilane to obtain CSP 1. The amino groups on CSP 1 were further end-capped with 3,5-dimethylbenzoyl chloride to give CSP 2. The silanols on CTDBS were end-capped with methyltrimethoxysilane to yield CSP 3. CSPs 1-3 were characterized by FTIR, solid-state 13C-NMR and elemental analysis. The enantioseparation abilities of CSPs 1-3 were evaluated with structurally various chiral analytes. The enantioseparation results demonstrated that the end-capping moieties on CSPs 1 and 2 significantly affected enantioseparation. In addition, the effect of the structures of chiral analytes and end- capping moieties on the retention factors and the resolutions was discussed.展开更多
A chiral stationary phase (CSP) was prepared by chemically bonding carboxymethyl-β-cyclodextrin (CM- β-CD) onto 3-aminopropyl silica gel through amidation reaction in water solution and was characterized by Four...A chiral stationary phase (CSP) was prepared by chemically bonding carboxymethyl-β-cyclodextrin (CM- β-CD) onto 3-aminopropyl silica gel through amidation reaction in water solution and was characterized by Fourier transform infrared spectroscopy (FT-IR), element analysis (EA) and thermal gravimetry analysis (TGA). The chromatographic performance was evaluated with 24 racemates under reversedphase conditions, The effect of salt, organic modifier, mobile phase pH and structures of analytes were discussed. In comparison with native β-CD bonded column, CYCLOBOND 12000, CM-β-CD CSP exhibited enhanced enantioseparation.展开更多
基金Supported by the National Natural Science Foundation of China(No.30160092)the Natural Science Foundation of Yunnan Province,China(No.2005E0006Z).
文摘Single-walled carbon nanotubes(SWNTs) have a high adsorption ability and nanoscale interactions. Cellulose trisphenylcarbamates possess high enantioseparation ability in high-performance liquid chromatography(HPLC). Single-walled carbon nanotubes mixed with cellulose trisphenylcarbamate are coated on the silica gel as chiral stationary phases and higher enantioseparation factors are obtained. After a single-walled carbon nanotube is linked to the 6-pesition of cellulose 2,3-bisphenylcarbamate, its enantioseparation resolution increases compared to that of the cellulose trisphenylcarbamate. It is the first time that SWNTs have been applied to enantioseparation. The results indicate that the single-walled carbon nanotubes are good promoters of chiral recognition. This method can be used to improve the enantioseparation efficiency of the polysaccharide chiral stationary phases.
基金supported by the National Science and Technology Special Projects (No.2009zx09301-003-5 -1 and2009zx09301-003-7-1)
文摘The enantiomers separation of thirteen drugs collected in Ch.P2010 was performed on chiral stationary phase of cellulose ramification (chiralpak OD and chiralpak OJ) by high performance liquid chromatographic (HPLC) methods, which included ibuprofen (C1), ketoprofen (C2), nitrendipine (C3), nimodipine (C4), felodipine (C5), omeprazole (C6), praziquantel (C7), propranolol hydrochloride (C8), atenolol (C9), sulpiride (C10), clenbuterol hydrochloride (C11), verapamil hydrochloride (C12), and chlorphenamine maleate (C13). The mobile phase consisted of isopropanol and n-hexane. The detection wavelength was set at 254 nm and the fiow rate was 0.7 mL/min. The enantiomers separation of these thirteen racemates on chiralpak OD column and chiralpak OJ column was studied, while the effects of proportion of organic additives, alcohol displacer and temperature on the separation were studied. And the mechanism of some of racemates was discussed. The results indicated that thirteen chiral drugs could be separated onchiral stationary phase of cellulose ramification in normal phase chromatographic system. The chromatographic retention and resolution of enantiomers could be adjusted by factors including column temperature and the concentration of alcohol displacer and organic alkaline modifier in mobile phase. It was shown that the resolution was improved with reducing concentration of alcohol displacer. When concentration of organic alkaline modifier was 0.2% (v/v), the resolution and the peak shape were fairly good. Most racemates mentioned above had better resolution at column temperature of 25 1C. When racemates were separated, the temperature should be kept so as to obtain stable separation results.
基金National Natural Science Foundation and Yunnan Province's Natural Science Foundation of China(No.20775066No.2005E0006Z).
文摘This paper presents the enantioseparation using glucose, cellobiose, lactose and raffinose as chiral selector bonded to silica gel via an arm in HPLC. Surprisingly, they also possess high enantioseparation selectivity, may be used in normal-phase and reversed- phase mode, and there is a big chiral discriminating complementary. This work indicates that oligosaccharides could soon become very attractive as a new class of chiral stationary phase for HPLC.
基金the National Natural Science Foundation of China (No. 20472111) is gratefully acknowledged.
文摘Three novel chiral selectors 4a-c were synthesized from (S)-amino acids and (R)-1-phenyl-2-(4-methylphenyl)ethylamine. 4a-c were connected to 3-aminopropylsilanized silica gel to be used as the chiral stationary phase for HPLC. Five amino acid derivatives and two pyrethroid insecticides were fairly resolved on these three new chiral stationary phases under normal phase condition.
文摘Three new hybrid organic/inorganic polymeric ligand-exchange chiral stationary phases were developed by radical chain transfer reaction and surface grafting on silica gel, and successfully used for the enantioseparations of DL-amino acids and DL-hydroxyl adds. The resolutions were achieved by using water containing 2.0 × 10^-4 mol/L of CuAc2 as a mobile phase, column temperature of 40 ℃, flow rate of 1.0 mL/min and detection at UV 254 nm. The elution order of D-isomer before L-isomer was observed for all DL-amino acids resolved except DL-Pro.
基金This work was supported by the National Natural Science Foundation of China (No. 20371037)the Natural Science Foundation of Hubei Province, China (No. 2002AB066).
文摘Two polyurethanes of different molecular weights were prepared by the copolymerization of phenyl diisocyanate and diisopropyl tartrate. The polyurethanes having terminal isocyanate groups were reacted with 3-aminopropyl silica gel to afford two chiral stationary phases. The M^- n of the two polyurethanes were 4057 g/mol and 6442 g/mol. The polyurethanes and the corresponding chiral stationary phases were characterized by FT-IR,^1 H NMR and elemental analysis. The loading capacities of the polyurethanes on silica gel were 0.68 mmol units/g and 0.61 mmol units/g, respectively. The separation performance and the influence of additives, triethylamine and trichloroacetic acid, on the separation of chiral compounds were investigated by HPLC. The chiral stationary phase prepared from polyurethane with M^- n of 4057 g/mol demonstrated better enantioseparation capability than that with M^- n of 6442 g/mol. Additionally, it was found that the addition of triethylamine and trichloroacetic acid in the mobile phases significantly improved the enantioseparation for these two chiral stationary phases.
基金Financial support from the National Natural Science Foundation of China (No.20572009)
文摘A novel chiral stationary phase (CSP) was prepared by immobilizing mono(6A-N-1-(2-hydroxyl)-phenylethylimino-6A- deoxy)-β-cyclodextrin onto the surface of silica gel via a longer spacer. This chiral stationary phase exhibited good enantioselectivity for a variety of chiral compounds under reversed-phase conditions.
文摘Amylose tris (phenylcarbamate) chiral stationary phase (ATPC-CSP) was prepared and used for optical resolution of clusters 1 and 2. n-Hexane/2-propanol ( 99/1; v/v) were found to be the most suitable mobile phase on ATPC-CSP.
文摘Three chiral stationary phases(CSPl, CSP2 and CSP3) for ligand-exchange chromatography were prepared by firstly using dimethylchlorosilane as an endcapping reagent for decreasing residual silanol groups on the surface of silica gel, and then modifying the surface of silica gel with allyl glycidyl ether and alkenes through the hydrosilation reaction, and lastly introducing L-proline as a chiral selector. The enantiomer resolutions of 14 amino acids and 2 hydroxyl acids were completed on the CSPs by using an aqueous solution of Cu(Ac)2 as mobile phase at a flow rate of 1.0 mL/min and column temperature of 40 ℃ with detection at UV 254 nm. In terms of enantioseleetivity a, column efficiency and resolution Rs, the chromatographic behaviors of the analytes on the CSPs were discussed via comparing them to those on the CSP4 prepared via the reference method. The results show that enantioselectivity a, column efficiency and resolution Rs of the analytes on the CSPs could be improved by using the above modifying method.
文摘Click chemistry was applied to immobilize L-proline derivative onto azide-modified silica gel to give a novel chiral stationary phase (denoted as click-CSP) for ligand exchange chromatography. The developed protocol combines the benefits of operational simplicity, exceptionally mild conditions and high surface loadings. The enantioselectivity α of some DL-arnino acids on the click- CSP were found to be in the range from 1.13 to 3.46. The chromatographic resolutions of some DL-amino acids and the stability study firmly illustrate the potential of click chemistry for preparation chiral stationary phase for ligand exchange chromatography.
文摘A new type of molecular imprinting stationary phase was prepared by using R- (+)-α -methylbenzy lamine as the print molecule. Experiments of high performance liquid chromatography show that the new stationary phase has high enantio-selectivity and discriminates (R, S) -(± )- α -methylbenzylamine successful ly with α value of 1. 67
文摘A novel chiral stationary phase (CSP1) for ligand-exchange chromatography (CLEC) was prepared by firstly using dimethylchlorosilane as an endcapping reagent for decreasing residual silanol group on the surface of silica gel, and then introducing L-Pro as a chiral selector and hydrophobic octyl group to the silica gel surface simultaneously. The enantioseparations of 14 DL-amino acids on CSP1 were achieved with the enantioselectivity α ranging from 1.09 to 2.44 and the resolution Rs being between 0.8 and 6.3. The chromatographic performances of CSP1 with the bonded phase (CSP2) prepared using reference method were compared. The results showed that the column efficiency and resolution Rs of chiral stationary phase could be improved by using the above modifying method.
文摘Several kinds of racemic naproxen ester were successfully separated on CTMB chiral stationary phase with hexane-ethanol (98:2, vol./vol.) as the mobile phase. The influence of mobile phase composition and structure of racemic naproxen ester on chiral separation was studied and the chiral recognition mechanism of CTMB was discussed.
文摘Excellent resolution of racemic 2-phenyl-1,1-cyclopropanedicarbonitrile and its nine analogues was accomplished using 100-5CH1-TBB chiral stationary phase under normal-phase HPLC conditions. The influence of mobile phase and the optimum conditions for the resolution of optically active enantiomers were investigated.
文摘The enantiomers separation of ei ght pharmaceutical racemates collected in Chinese Pharmacopoeia 2010(Ch.P2010),including nitrendipine,felodipine,omeprazole,praziquantel,sulpiride,clenbuterol hydrochloride,verapamil hydrochloride and chlorphenamine maleate,was performed on chiral stationary phase of amylose ramification by high performance liquid chromatography(HPLC)on Chiralpak AD-H column and Chiralpak AS-H column with the mobile phase consisted of isopropanol and n-hexane.The detection wavelength and the flow rate were set at 254 nm and 0.7 mL/min,respectively.The effects of proportion of organic additives,alcohol displacer and temperature on the separation were investigated.The results indicated that eight chiral drugs were separated on chiral stationary phase of amylase ramification in normal phase chroma tographic system.The chromatographic retention and resolution of enantiomers were adjusted by factors,including the changes of the concentration of alcohol displacer in mobile phase,organic alkaline modifier and column temperature.It was shown that the resolution was improved with reducing concentration of alcohol displacer.When the concentration of organic alkaline modifier was 0.2%,the resolution and the peak shape were fairly good.Most racemates mentioned above had the best resolution at column temperature of 25℃.The best temperature should be kept unchanged in the process of separation so as to obtain stable separation results.
文摘Cellulose tris(4-methylphenylcarbamate), amylosetris(3,5-di-methylphenylcarbamate) and amylose tris (phenylcarbamate) were prepared by the methodreported by Okamoto and were coated onto an aminopropylated mesoporous spherical silica gel. Thesefinal products were used as chiral stationary phases of high performance liquid chromatography forthe eighteen structurally related biphenyl compounds. The resolution was made using normal-phasemethodology with a mobile phase consisting of n-hexane-alcohol (ethanol, 1-propanol, 2-pro-panol or1-butanol). The effects of various aliphatic alcohols in the mobile phase were studied. Thestructural features of the solutes that influence then- k′ were discussed. A dominant effect oftrifluoroacetic acid on chiral separation of acidic solutes was noted.
基金financially supported by the National Key R&D Program of China (No.2019YFA0904104)。
文摘Chiral covalent organic frameworks(CCOFs) featuring chirality, stability, and good porosity have attracted a considerable amount of attention due to their important applications, such as asymmetric catalysis, chiral separation, and chiral recognition. In this study, a β-cyclodextrin(β-CD) covalent organic framework(β-CD-COF) diluted with polysiloxane OV-1701 was explored as a novel chiral stationary phase(CSP) for gas chromatography(GC) separation of racemates. The β-CD-COF coated capillary column had excellent selectivity, not only for the separation of linear alkanes, linear alcohols, fatty acid methyl esters mixture, the Grob mixture and positional isomers, but also for the resolution of chiral compounds, including chiral alcohols, aldehydes, ethers, and amino acid derivatives. In addition, the β-CD-COF-coated capillary column presented good repeatability and reproducibility. This work indicated the great potential of the CCOFs coated capillary column for the chromatographic separation of enantiomers.
基金financially supported by the National Natural Science Foundation of China(No.50973086)Hubei Provincial Department of Education of China(Z 20081501)
文摘A new method to prepare polysaccharide-coating type chiral stationary phases (CSPs) was developed in this work. As a typical example, naked silica gel was coated by cellulose, which was then derivatized with 3,5-dimethylbenzoyl chloride to afford cellulose tris(3,5-dimethylbenzoate)-silica gel (CTDBS) complex. The silanols on CTDBS were end-capped with 3- aminopropyltriethoxysilane to obtain CSP 1. The amino groups on CSP 1 were further end-capped with 3,5-dimethylbenzoyl chloride to give CSP 2. The silanols on CTDBS were end-capped with methyltrimethoxysilane to yield CSP 3. CSPs 1-3 were characterized by FTIR, solid-state 13C-NMR and elemental analysis. The enantioseparation abilities of CSPs 1-3 were evaluated with structurally various chiral analytes. The enantioseparation results demonstrated that the end-capping moieties on CSPs 1 and 2 significantly affected enantioseparation. In addition, the effect of the structures of chiral analytes and end- capping moieties on the retention factors and the resolutions was discussed.
文摘A chiral stationary phase (CSP) was prepared by chemically bonding carboxymethyl-β-cyclodextrin (CM- β-CD) onto 3-aminopropyl silica gel through amidation reaction in water solution and was characterized by Fourier transform infrared spectroscopy (FT-IR), element analysis (EA) and thermal gravimetry analysis (TGA). The chromatographic performance was evaluated with 24 racemates under reversedphase conditions, The effect of salt, organic modifier, mobile phase pH and structures of analytes were discussed. In comparison with native β-CD bonded column, CYCLOBOND 12000, CM-β-CD CSP exhibited enhanced enantioseparation.