EVALUATION OF C-18 SOLID-PHASE EXTRACTION CARTRIDGES FOR THE ISOLATION OF SELECT PESTICIDES AND METABOLITES

Nine different C-18 solid-phase extraction (SPE) cartridges were evalu ated for their efficiency at extracting nine pesticides and two s-tria zine metabolites from spiked deionized water samples. The SPE cartridg es were found to contain nitrogen (N) and/or phosphorus (P) contaminan ts and varied in their extraction efficiency for certain pesticides an d metabolites. Four of the nine SPE cartridges gave acceptable (70 to 120%) pesticide and metabolite recovery percentages, while five cartri dges had marginal (50 to 70%) to poor (< 50%) recoveries. Statistical analyses showed that the poor to marginal recoveries found for three c ompounds could not be explained by considering several indigenous chem ical and physical traits of the cartridge. It is suggested that proper SPE cartridge selection for pesticide recovery should be evaluated us ing several different cartridges.