NANOMOLAR DERIVATIZATIONS WITH 5-CARBOXYFLUORESCEIN SUCCINIMIDYL ESTER FOR FLUORESCENCE DETECTION IN CAPILLARY-ELECTROPHORESIS

The ability of 5-carboxyfluorescein succinimidyl ester (CFSE) to deriv atize amino acids at very low concentrations has been investigated. CF SE can derivatize nanomolar concentrations of amino acids, which repre sents a 1000-fold improvement compared to fluorescein isothiocyanate ( FITC). Although the reactive probe is not fluorogenic, few hydrolysis products result from derivatization, leading to relatively clean elect ropherograms compared to FITC derivatization. Derivatizations of gamma -aminobutyric acid suggest that CFSE may be a practical amine-reactive fluorescent probe for the quantification of neurotransmitters in micr odialysates. (C) 1998 Elsevier Science B.V. All rights reserved.