ONLINE TRACE ENRICHMENT OF POLAR PESTICIDES IN ENVIRONMENTAL WATERS BY REVERSED-PHASE LIQUID-CHROMATOGRAPHY DIODE-ARRAY DETECTION-PARTICLE BEAM MASS-SPECTROMETRY

The determination of a group of pesticides by RPLC-diode array detection, coupled on-line to particle beam MS, is developed for the analysis of different environmental waters. On-line trace enrichment of 100 ml of sample on a PLRP-S precolumn allows the determination of most pesticides at levels between 0.2 and 5 mu g l(-1) and detection limits in the range 0.05-0.5 mu g l(-1) for diode array detection and 0.02-0.5 mu g l(-1) for particle beam MS. With real-life samples, a distinct matrix effect is observed in particle beam MS detection, which is caused by coeluting compounds acting as carriers. This improves analyte detectability and requires standard addition to be used for quantification. Different river and drinking waters were analysed and some pollutants were detected at sub- mu g l(-1) levels.