Gas chromatographic determination of organochlorine and organophosphorus pesticides in human fluids using solid phase microextraction

This paper explores the feasibility of developing procedures based on solid phase microextraction (SPME) for the determination of pesticides in human body fluids, including serum and urine samples. The advantages of SPME proc edures could greatly help in sample treatment reduction that is highly reco mmendable in biological monitoring for pesticides. Two procedures based on direct immersion SPME and GC/ECD/FPD analysis were investigated for organochlorine (hexachlorobenzene, beta -HCH, lindane, del ta -HCH, endosulfan ether, heptachlor, aldrin, heptachlor epoxide, alpha -e ndosulfan, p,p'-DDE, endrin, beta -endosulfan, p,p'-DDD, endosulfan sulphat e, p,p'-DDT, methoxychlor) and organophosphorus pesticides (diazinon, parat hion methyl, fenitrothion, malathion, fenthion, chlorpyrifos, methidathion) in serum and urine samples. Quantitative application of SPME for the deter mination of selected pesticides in biological fluids required dilution of s amples prior to SPME, in order to reduce matrix influence on the extraction of pesticides, and the use of surrogate standards for accurate quantitatio n. In this way, quantitation can be carried out by means of external standa rds prepared in ultra-pure water. Optimised procedures were applied to spik ed samples in order to obtain analytical characteristics. Recoveries obtain ed were generally satisfactory and over 70% in most cases, with relative st andard deviations in the range of 1-20% at all concentration levels tested. Limits of detection, calculated as the signal equal to three times backgro und noise using chromatograms of samples spiked at the lowest level, were i n the range of 1-10 ng ml(-1) for serum samples (delta -HCH, 20 ng ml(-1) a nd methidathion, 15 ng ml(-1)), and in the range of 0.1-0.4 ng ml(-1) for o rganophosphorus pesticides in urine samples (methidathion, 20 ng ml(-1)). F inally, developed procedures were applied to real-world samples obtained fr om exposed and non-exposed subjects, several organochlorine pesticides bein g detected in some of the samples. (C) 2001 Elsevier Science B.V. All right s reserved.