Results 71 to 80 of about 410 (110)
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Journal of Chromatography A, 1994
A new mode of pH-zone-refining counter-current chromatography operates in a manner analogous to displacement chromatography. The method uses a retainer base (acid) in the stationary phase to retain analytes in the column and a displacer acid (base) to elute the analytes in the decreasing order of pKa and hydrophobicity.
Y, Ito, Y, Ma
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A new mode of pH-zone-refining counter-current chromatography operates in a manner analogous to displacement chromatography. The method uses a retainer base (acid) in the stationary phase to retain analytes in the column and a displacer acid (base) to elute the analytes in the decreasing order of pKa and hydrophobicity.
Y, Ito, Y, Ma
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Journal of Chromatography A, 2008
This work concentrates on pH-zone-refining counter-current chromatography of two isomeric dicaffeoylquinic acids, 3,5-dicaffeoylquinic acid and 3,4-dicaffeoylquinic acid along with 3-caffeoylquinic acid, from crude extracts of Flos Lonicerae. The elution sequence of the isomeric dicaffeoylquinic acids, the mixing zone and mechanism of separation are ...
Shengqiang, Tong +2 more
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This work concentrates on pH-zone-refining counter-current chromatography of two isomeric dicaffeoylquinic acids, 3,5-dicaffeoylquinic acid and 3,4-dicaffeoylquinic acid along with 3-caffeoylquinic acid, from crude extracts of Flos Lonicerae. The elution sequence of the isomeric dicaffeoylquinic acids, the mixing zone and mechanism of separation are ...
Shengqiang, Tong +2 more
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Journal of Separation Science, 2010
AbstractPreparative separation of alkaloids from embryo of the seed of Nelumbo nucifera Gaertn has been successfully performed for the first time using pH‐zone‐refining counter‐current chromatography. Two kinds of two‐phase solvent systems were applied to preparative CCC isolation.
Xiao, Wang +5 more
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AbstractPreparative separation of alkaloids from embryo of the seed of Nelumbo nucifera Gaertn has been successfully performed for the first time using pH‐zone‐refining counter‐current chromatography. Two kinds of two‐phase solvent systems were applied to preparative CCC isolation.
Xiao, Wang +5 more
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Journal of Chromatography A, 2002
pH-Zone-refining counter-current chromatography was successfully applied to the separation of the main components of Food Color Red No. 106 (R-106, acid red, Color Index No. 45100). A 300-mg quantity of sample was separated using the following two-phase solvent system: n-butanol-water, 40 mM sulfuric acid in organic stationary phase and 30 mM ammonia ...
Hisao, Oka +8 more
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pH-Zone-refining counter-current chromatography was successfully applied to the separation of the main components of Food Color Red No. 106 (R-106, acid red, Color Index No. 45100). A 300-mg quantity of sample was separated using the following two-phase solvent system: n-butanol-water, 40 mM sulfuric acid in organic stationary phase and 30 mM ammonia ...
Hisao, Oka +8 more
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Journal of Chromatography A, 1994
The application of pH-zone-refining counter-current chromatography (CCC) to the preparative separation of stereoisomeric acids is described. The separation was accomplished on the basis of the difference in acidity of the two stereoisomers.
C, Denekamp +3 more
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The application of pH-zone-refining counter-current chromatography (CCC) to the preparative separation of stereoisomeric acids is described. The separation was accomplished on the basis of the difference in acidity of the two stereoisomers.
C, Denekamp +3 more
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Journal of Chromatography A, 2021
Ferulic acid stereoisomers are the most abundant phenolic acids in cereal bran. However, it is challenging to separate them because of the similar structures and properties. In this study, a preparative separation method of ferulic acid stereoisomers from the crude extract of wheat bran was successfully developed.
Yingying, Tang +3 more
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Ferulic acid stereoisomers are the most abundant phenolic acids in cereal bran. However, it is challenging to separate them because of the similar structures and properties. In this study, a preparative separation method of ferulic acid stereoisomers from the crude extract of wheat bran was successfully developed.
Yingying, Tang +3 more
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Journal of Chromatography A, 2014
pH-zone-refining counter-current chromatography was successfully applied to the preparative separation of five quaternary ammonium alkaloids from the crude extract of Coptis chinensis Franch. The separation was performed with a two-phase solvent system composed of chloroform-methanol-water (4:3:3, v/v), where the upper aqueous stationary phase was ...
Changlei, Sun +5 more
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pH-zone-refining counter-current chromatography was successfully applied to the preparative separation of five quaternary ammonium alkaloids from the crude extract of Coptis chinensis Franch. The separation was performed with a two-phase solvent system composed of chloroform-methanol-water (4:3:3, v/v), where the upper aqueous stationary phase was ...
Changlei, Sun +5 more
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Journal of Chromatography B, 2010
Two modes of high-speed counter-current chromatography (HSCCC) were successfully applied to the separation of alkaloids from crude extract of Nelumbo nucifera leaves. The conventional HSCCC separations were performed with a two-phase solvent system composed of tetrachloromethane-CHCl3-methanol-0.1 M HCl at a volume ratio of 1:3:3:2 (v/v/v/v), and 120 ...
Zhenjia, Zheng +5 more
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Two modes of high-speed counter-current chromatography (HSCCC) were successfully applied to the separation of alkaloids from crude extract of Nelumbo nucifera leaves. The conventional HSCCC separations were performed with a two-phase solvent system composed of tetrachloromethane-CHCl3-methanol-0.1 M HCl at a volume ratio of 1:3:3:2 (v/v/v/v), and 120 ...
Zhenjia, Zheng +5 more
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Food Chemistry, 2012
Abstract Ganoderma lucidum is a famous fungus. The triterpenoids are the main bioactive components and exhibit various pharmacological activities. However, the scarcity of the pure triterpenoid has greatly restrained the modern research of G. lucidum.
Chun-Ru Cheng +6 more
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Abstract Ganoderma lucidum is a famous fungus. The triterpenoids are the main bioactive components and exhibit various pharmacological activities. However, the scarcity of the pure triterpenoid has greatly restrained the modern research of G. lucidum.
Chun-Ru Cheng +6 more
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Journal of Chromatography A, 1998
pH-Zone-refining counter-current chromatography was applied to the separation of alkaloids from a crude extract of the root of Sophora flavescens Ait using a multilayer coil planet centrifuge. After methyl tert.-butyl ether and water were equilibrated, triethylamine (10 mM) was added to the organic phase as a retainer and hydrochloric acid (5-10 mM) to
F, Yang, J, Quan, T, Zhang, Y, Ito
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pH-Zone-refining counter-current chromatography was applied to the separation of alkaloids from a crude extract of the root of Sophora flavescens Ait using a multilayer coil planet centrifuge. After methyl tert.-butyl ether and water were equilibrated, triethylamine (10 mM) was added to the organic phase as a retainer and hydrochloric acid (5-10 mM) to
F, Yang, J, Quan, T, Zhang, Y, Ito
openaire +2 more sources