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Temperature effects on the enantioselectivity of basic analytes in capillary EKC using sulfated β‐CDs as chiral selectors
Author(s) -
Peng ZhenLei,
Yi Fei,
Guo Baoyuan,
Lin JinMing
Publication year - 2007
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200700157
Subject(s) - chemistry , ephedrine , enthalpy , analyte , sulfation , chromatography , capillary action , capillary electrophoresis , thermodynamics , physics , neuroscience , biology , biochemistry
The thermodynamic processes were investigated to reveal the temperature effects during chiral separation by capillary EKC with reversed polarity mode using sulfated β‐CD (S‐β‐CD) as chiral selectors. The temperature effects on enantioselectivities of basic analytes (ephedrine, norephedrine, synephrine, and epinephrine) were investigated in detail over a temperature range of 20–60°C. An increase of the capillary temperature produced the decrease of enantioselectivities for ephedrine and norephedrine, but increase of enantioselectivities for synephrine and epinephrine. The thermodynamic variations showed that the interactions between the basic analytes and chiral selectors were always enthalpy‐ driven. However, the difference in enthalpy and entropy showed that the enantioseparation was an enthalpy‐driven process for ephedrine and norephedrine, but an entropydriven process for synephrine and epinephrine. Just because of the different driving forces, there exist two kinds of temperature effects on enantioselectivities mentioned above.