Gas chromatographic determination of selected pesticides in human serum by head-space solid-phase microextraction

A simple and rapid method, employing head-space solid-phase microextraction then gas chromatography-mass spectrometry, has been developed for the simultaneous determination of nine organochlorine pesticides (alpha -HCH, hexachlorobenzene, lindane, endosulfan ether, alpha -endosulfan, pp'-DDE, p,p'-DDD, endosulfan sulfate, and p,p'-DDT) and five organophosphorus pesticides (fonofos, parathion methyl, fenitrothion, chlorpyrifos, and ethion) in human serum. Sulfuric acid (9 M, 50 muL), water (2 mL), and surrogate/internal standard solution (p,p'-DDE-D-8 hexachlorobenzene-C-13(6), and fenitrothion D-6; 50 muL) were added to the serum sample (1 mL) and the resulting solution was sampled by head-space SPME of 90 degreesC for 30 min. Quantitation was performed by means of calibration curves prepared by use of serum, using areas relative to those of the surrogates. Precision was found to be better than 20% at three concentration levels assayed in the ng mL(-1) range. The detection limits were in the range 0.1 to 6 ng mL(-1) for all compounds. Finally, application of the optimized procedure enabled the detection of some pesticides in serum samples obtained from agricultural workers. Hexachlorobenzene, pp'-DDE, and chlorpyrifos were found most frequently in the samples analyzed.