Solid Phase Extraction of Pesticides with Determination by Gas Chromatography Gas Chromatography

A simple, rapid, and effectivemethod for the extraction of fifteenorganochlorine and organophosphorus pesticides based on the use of solid phaseBond Elut C-18 cartridges was studied as an alternative method to those based on extraction with organic solvents.Solidphase extraction is an attractive chromatographic samplepreparation technology that reduces analysis time, costs, labor, and solventconsumptionrelative to traditionalliquid/liquid extraction methods. The samplerecoveries with the use of solid phase extractions were excellent for most pesticides. Analyte concentration by a factor as great as 1000-fold was achieved readily.The adsorbed pesticideswere eluted from the solid phase by an organic solvent. The influence of the elution solvent was studied.The best recoveries were obtained using methanol. The detection of the pesticides was made using OV-17megabore capillarygas chromatography (GC) withelectron capture detection.Pesticide extraction efficienciesusing C18cartridges ranged from 64-100%, with the exception of mirex which was 56%at 0.2ug/L spikinglevels.Recovery precision studies demonstrate that relative standard deviations range from 1 to 9%.The compounds were identifiedby comparing the retention time with that of a standard under the same GC conditions,and quantitation was accomplished by comparing the peak areas.