Modern porous monoliths have been conceived as a new class of stationary phases for high performance liquid chromatography(HPLC) in classical columns in the early 1990s and later extended to the capillary format.These...Modern porous monoliths have been conceived as a new class of stationary phases for high performance liquid chromatography(HPLC) in classical columns in the early 1990s and later extended to the capillary format.These monolithic materials are prepared using simple processes carried out in an external mold(inorganic monoliths) or within the confines of the column(organic monoliths and all capillary columns).These methods afford macroporous materials with large through-pores that enable applications in a rapid flow-through mode.Since all the mobile phase must flow through the monolith,the convection considerably accelerates mass transport within the monolithic separation medium and improves the separations.As a result,the monolithic columns perform well even at very high flow rates.The applications of monolithic capillary columns are demonstrated on numerous separations in the HPLC mode.展开更多
Molecular imprinting chiral stationary phase against Cbz-L-Serine (Cbz-L-Ser) and Cbz-L-Alaine (Cbz-L-Ala) were prepared utilizing acrylamide + 2-vinylpyridine as combined basic functional monomers. Cross-selectivity ...Molecular imprinting chiral stationary phase against Cbz-L-Serine (Cbz-L-Ser) and Cbz-L-Alaine (Cbz-L-Ala) were prepared utilizing acrylamide + 2-vinylpyridine as combined basic functional monomers. Cross-selectivity was used to obtain simultaneous chiral separations of Cbz-DL-Ser and Cbz-DL-Ala by connecting two columns packed with Cbz-L-Ser and Cbz-L-Ala imprinted chiral stationary phase, respectively.展开更多
Bi-2-naphthol(BINOL) enantiomers were baseline resolved on HPLC network-polymeric chiral stationary phase (Kromasil CHI-DMB, based on O,O′-di(3,5-dimethylbenzoyl)N,N′-diallyl-L-tartaric diamide). The effects of the ...Bi-2-naphthol(BINOL) enantiomers were baseline resolved on HPLC network-polymeric chiral stationary phase (Kromasil CHI-DMB, based on O,O′-di(3,5-dimethylbenzoyl)N,N′-diallyl-L-tartaric diamide). The effects of the column temperature, the type and the concentration of the polar alcohol modifier in the binary mobile phase on the chiral resolution were examined. The separation value was 1.191 when V(hexane)∶V(2-propanol)=95∶5 was used as mobile phase at a flow rate of 1.0 mL/min at 25 ℃ with retention time being within 14 minutes. The mechanism of the chiral recognition was discussed with the calculated thermodynamic parameters. It is suggested that hydrogen bonding interaction between hydroxyl group of the solute and the CSP play important roles in chiral recognition. The chiral resolution is enthalpy-entropy driven and the enthalpy contribution is greater. 1,1′-Bi-2-naphthyl di-p-toluenesulfonate, 1,1′-bi-2-naphthyl diacetate and 1,1′-bi-2-naphthyl dicinnamate could not be resolved at experiment conditions used.展开更多
基金Grant in AidforScientificResearchfromTheJapanSocietyforthePromotionofScience(JSPS) ,Grant in AidforYoungScientistsfromTheMinistryofEducation ,Culture ,Sports ,ScienceandTechnology (MEXT)
基金Supported by grants of the National Institute of General Medical Sciences,National Institutes of Health(GM-48364),and the Materials Sciences and Engineering Division of the U.S.Department of Energy(DE-AC02-05CH11231).
文摘Modern porous monoliths have been conceived as a new class of stationary phases for high performance liquid chromatography(HPLC) in classical columns in the early 1990s and later extended to the capillary format.These monolithic materials are prepared using simple processes carried out in an external mold(inorganic monoliths) or within the confines of the column(organic monoliths and all capillary columns).These methods afford macroporous materials with large through-pores that enable applications in a rapid flow-through mode.Since all the mobile phase must flow through the monolith,the convection considerably accelerates mass transport within the monolithic separation medium and improves the separations.As a result,the monolithic columns perform well even at very high flow rates.The applications of monolithic capillary columns are demonstrated on numerous separations in the HPLC mode.
文摘Molecular imprinting chiral stationary phase against Cbz-L-Serine (Cbz-L-Ser) and Cbz-L-Alaine (Cbz-L-Ala) were prepared utilizing acrylamide + 2-vinylpyridine as combined basic functional monomers. Cross-selectivity was used to obtain simultaneous chiral separations of Cbz-DL-Ser and Cbz-DL-Ala by connecting two columns packed with Cbz-L-Ser and Cbz-L-Ala imprinted chiral stationary phase, respectively.
文摘Bi-2-naphthol(BINOL) enantiomers were baseline resolved on HPLC network-polymeric chiral stationary phase (Kromasil CHI-DMB, based on O,O′-di(3,5-dimethylbenzoyl)N,N′-diallyl-L-tartaric diamide). The effects of the column temperature, the type and the concentration of the polar alcohol modifier in the binary mobile phase on the chiral resolution were examined. The separation value was 1.191 when V(hexane)∶V(2-propanol)=95∶5 was used as mobile phase at a flow rate of 1.0 mL/min at 25 ℃ with retention time being within 14 minutes. The mechanism of the chiral recognition was discussed with the calculated thermodynamic parameters. It is suggested that hydrogen bonding interaction between hydroxyl group of the solute and the CSP play important roles in chiral recognition. The chiral resolution is enthalpy-entropy driven and the enthalpy contribution is greater. 1,1′-Bi-2-naphthyl di-p-toluenesulfonate, 1,1′-bi-2-naphthyl diacetate and 1,1′-bi-2-naphthyl dicinnamate could not be resolved at experiment conditions used.
