The macrocyclic dioxopolyamine compounds, 1,4,7,10-tetraazacyclotridecane-11,13-diones were used as stationary phases with the aid of 3-(2-cyclooxypropoxyl)propyl-trimethoxy silane as a bridge in open-tubular capillar...The macrocyclic dioxopolyamine compounds, 1,4,7,10-tetraazacyclotridecane-11,13-diones were used as stationary phases with the aid of 3-(2-cyclooxypropoxyl)propyl-trimethoxy silane as a bridge in open-tubular capillary electrochromatography(OTCEC). The capillaries were etched by aqueous sodium before being coated. These modified capillaries had shown improved separations of neurotransmitters, isomeric dihydrobenzenes, isomeric nitrophenols and isomeric aminophenols in comparison with untreated capillaries.展开更多
Two chiral stationary phases(BCDs and YBCDs) were prepared by bonding β-cyclodextrin derivative with α-Schiff base group from β-cyclodextrin monoaldehyde to the sillica gel via 3-glyci-{dyloxypropyltrimethoxysilane...Two chiral stationary phases(BCDs and YBCDs) were prepared by bonding β-cyclodextrin derivative with α-Schiff base group from β-cyclodextrin monoaldehyde to the sillica gel via 3-glyci-{dyloxypropyltrimethoxysilane} as a coupling agent. Using acetonitrile-TEAA as mobile phase, good enantiomeric resolutions were obtained for DL-aminoacide on BCDs and YBCDs, including Leucine, Threonine and Valine. It is also observed that the higher separation factor of threonine was at pH {7.11} for both of the column, and the optimal column temperatures of Leucine appeared at 30 ℃ or {40 ℃}, respectively for YBCDs and BCDs.展开更多
A novel chiral bonded stationary phase(CBSP) for ligand exchange chromatography was prepared by bonding ( S ) 1,2,3,4 tetrahydro 3 isoquinoline carboxylic acid prepared from L Phe to YWG 80 silica gel via 3 glycidylox...A novel chiral bonded stationary phase(CBSP) for ligand exchange chromatography was prepared by bonding ( S ) 1,2,3,4 tetrahydro 3 isoquinoline carboxylic acid prepared from L Phe to YWG 80 silica gel via 3 glycidyloxypropyltrimethoxysilane as a coupling agent. Chromatographic resolutions of some DL amino acids were achieved on the CBSP by using an aqueous solution of 2 mmol/L N(C 2H 5) 3, 2 mmol/L HAc and 0 2 mmol/L Cu(Ac) 2 as the mobile phase with a flow rate 1 0 mL/min, column temperature 50 ℃ and detection at 254 nm. The enantioselectivity α of the DL amino acids on the CBSP was found to be between 1 11 and 1 51. The elution order of D isomer before L isomer on the CBSP was observed for all the DL amino acids resolved except DL Val. For DL Pro, DL Val and DL Leu the elution order through the CBSP was different from that through the chiral ligand exchange phases prepared from L Pro or L hydroxyl proline with a five\|membered ring structure. [WT5HZ]展开更多
文摘The macrocyclic dioxopolyamine compounds, 1,4,7,10-tetraazacyclotridecane-11,13-diones were used as stationary phases with the aid of 3-(2-cyclooxypropoxyl)propyl-trimethoxy silane as a bridge in open-tubular capillary electrochromatography(OTCEC). The capillaries were etched by aqueous sodium before being coated. These modified capillaries had shown improved separations of neurotransmitters, isomeric dihydrobenzenes, isomeric nitrophenols and isomeric aminophenols in comparison with untreated capillaries.
文摘Two chiral stationary phases(BCDs and YBCDs) were prepared by bonding β-cyclodextrin derivative with α-Schiff base group from β-cyclodextrin monoaldehyde to the sillica gel via 3-glyci-{dyloxypropyltrimethoxysilane} as a coupling agent. Using acetonitrile-TEAA as mobile phase, good enantiomeric resolutions were obtained for DL-aminoacide on BCDs and YBCDs, including Leucine, Threonine and Valine. It is also observed that the higher separation factor of threonine was at pH {7.11} for both of the column, and the optimal column temperatures of Leucine appeared at 30 ℃ or {40 ℃}, respectively for YBCDs and BCDs.
文摘A novel chiral bonded stationary phase(CBSP) for ligand exchange chromatography was prepared by bonding ( S ) 1,2,3,4 tetrahydro 3 isoquinoline carboxylic acid prepared from L Phe to YWG 80 silica gel via 3 glycidyloxypropyltrimethoxysilane as a coupling agent. Chromatographic resolutions of some DL amino acids were achieved on the CBSP by using an aqueous solution of 2 mmol/L N(C 2H 5) 3, 2 mmol/L HAc and 0 2 mmol/L Cu(Ac) 2 as the mobile phase with a flow rate 1 0 mL/min, column temperature 50 ℃ and detection at 254 nm. The enantioselectivity α of the DL amino acids on the CBSP was found to be between 1 11 and 1 51. The elution order of D isomer before L isomer on the CBSP was observed for all the DL amino acids resolved except DL Val. For DL Pro, DL Val and DL Leu the elution order through the CBSP was different from that through the chiral ligand exchange phases prepared from L Pro or L hydroxyl proline with a five\|membered ring structure. [WT5HZ]
