DETERMINATION OF PESTICIDES BY ONLINE TRACE ENRICHMENT - REVERSED-PHASE LIQUID-CHROMATOGRAPHY - DIODE-ARRAY DETECTION AND CONFIRMATION BY PARTICLE-BEAM MASS-SPECTROMETRY

A group of pesticides has been determined by liquid chromatography wit h diode-array detection (DAD). The coupling of a particle-beam (PB) ma ss spectrometer to the outlet of the DAD enabled the identities of the pesticides to be confirmed from mass spectra obtained by electron imp act ionization. On-line trace enrichment of 200 mL of sample with a PL RP-S precolumn enabled most pesticides to be determined in real sample s at levels between 0.2 and 5 mu g L(-1) and with limits of detection (LOD) between 0.05 and 0.5 mu g L(-1) In the analysis of real samples, one of the pesticides studied was determined by DAD and its identity was confirmed by comparison of PB mass spectra. The use of PB-MS also enabled the detection of non-target compounds.