Separation selectivity patterns of fully charged achiral compounds in capillary electrophoresis with a neutral cyclodextrin

Authors

  • Wasura Soonthorntantikul,

    1. Chromatography and Separation Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
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  • Monpichar Srisa-art,

    1. Chromatography and Separation Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
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  • Natchanun Leepipatpiboon,

    1. Chromatography and Separation Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
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  • Thumnoon Nhujak

    Corresponding author
    • Chromatography and Separation Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
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Correspondence: Assoc. Prof. Thumnoon Nhujak, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand

E-mail: thumnoon.n@chula.ac.th

Fax: +66-2-218-7598

Abstract

Based on the separation selectivity equation, related to the dimensionless parameters for fully charged achiral analytes using a neutral CD, the separation selectivity can be classified into seven patterns. With respect to CZE without CD, the presence of CD in the buffer may improve, or reduce, the separation selectivity with this effect being accompanied by the same or reversed electrophoretic mobility order for charged analytes. This can depend on the separation selectivity of the two analytes in free solution, the binding selectivity, the separation selectivity of analyte–CD complexes and the ratio of electrophoretic mobility of the analytes in free, and complexed forms. Using positional isomers of benzoic acids and phenoxy acids as test analytes and α-CD as a selector, the observed separation selectivity shapes were found to be in excellent agreement with the predicted separation selectivities.

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