Analysis of environmental pollutants metabolized from pesticides using capillary electrophoresis with multiphoton-excited fluorescence detection

Multiphoton-excited fluorescence by diode laser of continuous wave was uniquely developed for capillary electrophoresis to determine aniline species metabolized from pesticides. To achieve 2-photon excitation fluorescence, derivatization procedure was performed using fluorescein isothiocyanate (FITC). The concentration ratio of FITC to the analytes was discussed for quantitative analysis. Several parameters that influenced separation quality of capillary zone electrophoresis were investigated, such as applied voltage, buffer pH value and concentration, etc. Under the optimized conditions, four pesticide residues were completely separated and determined within 4 min, with detection limit down to zepptomole level (calculated detection volume: 45.0 aL). Quantitative analyses exhibited excellent linear dynamic relationship in the range of about two orders of magnitude. The established method was further validated by testing spiked lake water sample.