SCREENING AND ANALYSIS OF POLAR PESTICIDES IN ENVIRONMENTAL MONITORING PROGRAMS BY COUPLED-COLUMN LIQUID-CHROMATOGRAPHY AND GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

Screening and analysis of polar pesticides based on coupled-column rev ersed-phase liquid chromatography (LC-LC) and GC- or LC-MS is a powerf ul tool in the execution of environmental monitoring programmes. This paper presents a unified approach utilising LC-LC screening followed b y GC-MS confirmation. As polar pesticides are not generally amenable t o GC a widely applicable derivation technique is used. The results dem onstrate that the proposed LC and MS techniques are capable of analysi ng a wide range of polar pesticides down to levels of 0.1 mu g/l (EU l imit for drinking water). LC switching techniques for group analysis o r individual compounds rely on the reversed-phase retention and the UV detectability of the pesticides in combination with the choice of the LC columns. Fast miniaturised derivatization prior to GC-MS forms an integral part in the proposed strategy. In order to avoid extraction l osses, derivation in the aqueous sample, preferably with electrophoric reagents with enhanced sensitivity in GC-NICI-MS are employed where p ossible. In this communication, method development and validation fitt ing in the strategy are evaluated and the results of the combined appr oach are discussed.