Analytical methodology for screening organophosphorus pesticides in biota samples

The use of gel permeation chromatography (GPC) and capillary gas chromatography (GC) with thermionic detection (NPD) is described as a routine methodology for the determination of organophosphorus pesticides in biota samples. Confirmatory analysis is done by capillary GC with mass spectrometry in the negative chemical ionization mode (NCI-MS). As an example, the use of GPC is described as trace-enrichment technique and clean-up to remove coextractive lipids in samples of mosquito fish Gambussia affinis collected during periods of 1987-1989 in the rice crop fields of the Ebro Delta (Spain). Recoveries of dioxathion, fenitrothion, malathion, tetrachlorvinphos, azinphos-ethyl, ronnel and coumaphos varied between 60% and 80% depending on the compound.