On-column derivatization for the analysis of homocysteine and other thiolsby capillary electrophoresis with laser-induced fluorescence detection

On-column derivatization and capillary electrophoresis (CE) with laser-indu ced fluorescence (LIF) detection has been developed for the fully automated assay of homocysteine and other thiols. The unique feature of this CE tech nique comes from the direct injection of a sample including homocysteine, e nabling the derivatization with 4-aminosulfonyl-7-fluoro-2,1,3-benzoxadizol e (ABD-F) to be accomplished in the capillary. After the derivatization for 10 min at 50 degrees C, the homocysteine was analyzed within 7 min under a n applied electric field of 333 V cm(-1). The detection limit obtained for homocysteine with on-column LIF detection was 5.0 nM, as compared to 2.5 nM with pre-column LIF detection. The method is a very simple, fast, and prac tical approach for the fully automated assay of homocysteine and other thio ls contained in low-volume and low-concentration samples. (C) 2000 Elsevier Science B.V. All rights reserved.