Development of a capillary zone electrophoretic method for the rapid separation and detection of hepatotoxic microcystins

Analysis of trace amounts of various hepatotoxic microcystins in marine and freshwater samples is very important since these toxins, especially microc ystin-LR, have been demonstrated to have tumour-promoting activity. In this study, instead of measuring the total amount of microcystins, we developed a capillary zone electrophoretic method for the separation and detection o f individual toxin standards. No additives were used for enhancement of res olution. This technique is characterized by a high separation efficiency, s hort analysis time and small sample volume. In order to improve the detecti on sensitivity, a laser-induced fluorescence detector was used, and the lab elling of microcystins was accomplished through a two-step procedure. First , the microcystin standards were converted into cysteine conjugates, follow ed by derivatization with Fluorescein 5-Isothiocyanate (FITC). After deriva tization, the FITC-labelled microcystins were directly injected, separated and detected in 8 min. This method was shown to be a promising technique fo r sensitive and rapid analysis of individual microcystin toxins. (C) 1999 E lsevier Science Ltd, All rights reserved.