Electrically driven microseparation methods for pesticides and metabolites: V. Micellar electrokinetic capillary chromatography of aniline pesticidic metabolites derivatized with fluorescein isothiocyanate and their detection in real water at low levels by laser-induced fluorescence

Anilines are important pollutants occurring in the environment as industrial discharges as well as the transformation products (i.e., metabolites) of a wide variety of commonly used pesticides. In this report, we describe the precolumn derivatization of anilines with fluorescein isothiocyanate (FITC) and their subsequent separation and detection by capillary electrophoresis-laser induced fluorescence (CE-LIF) detection. The FITC-aniline derivatives were readily detected at the 10(-10) M level. This limit of detection (LOD) was achieved in the presence of glycosidic surfactants complexed with borate at alkaline pH yielding the so-called in situ charged micelles. The glycosidic surfactants evaluated were n-octyl- and n-nonylglucopyranoside. Furthermore, and under optimum conditions, the FITC precolumn derivatization of the anilines was performed in real water (e.g., tap and lake water) spiked with anilines at the LOD level. The water matrices showed marginal effects on the extent of derivatization at the LOD level, and the possible interferents in the water samples did not affect the FITC-solute signal due to the selectivity of the derivatization and detection schemes. Besides filtration from microparticles, the real water samples did not necessitate extensive sample cleanup prior to derivatization.