Simultaneous determination of pyrethroid,organophosphate, and organochlorine pesticides in fish tissue using tandem solid-phase extraction clean-up

A method was developed for the simultaneous analysis of pyrethroid, organophosphate, and organochlorine pesticides in fish tissue. Different extraction solvents and solid-phase extraction clean-up procedures were tested. The best approach was to extract by sonication with acetonitrile and 10%?methanol, followed by clean-up of extracts using C₁₈, Florisil and Na₂SO₄ tandem solid-phase extraction cartridges. Gas chromatography with an electron-capture detector was used for analyte determination. All 26 target pesticides were detected using the new method in a single analytical run. The method detection limits ranged from 0.13 to 1.40?µg/kg, while recoveries of the analytes ranged from 86.1 to 133.8%?with relative standard deviations?≤12.1%?at a spiked concentration of 5?µg/kg. The method was developed to assess possible pesticide contamination in fish collected from lakes at a proposed Illinois National Guard Armory site.