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Objective：To develop a rapid and quantitative analysis method for determiningmethomyl and three kinds of metabolites of malathion involving DMP,DMTP,DMDTP in urine by Solid phase extraction-gas chromatography massspectrometry (SPE-GS/MS). SPE-GS/MS was also used in the detection of malathionand methomyl and their metabolite in rat urine.Methods：The urine sample pretreatment method, the test conditions, therecovery rate, the specificity, the precision, the detection limit, the stability wereinvestigated by using rat urine spiked with standard DMP, DMTP,DMDTP andmethomyl. A rapid qualitative and quantitative analysis method was developed fordetermining DMP, DMTP, DMDTP, and methomyl in urine by SPE-GS/MS.DMP, DMTP, DMDTP, and methomyl in rat urine were determinated in differenttime periods. At the same time, creatinine in rat urine was determinated in differenttime periods to calibrate the targets concent. After the intragastric administration withDMP, DMTP, DMDTP, and methomyl, the rat urine was collected at0.5h，1h，2h，3h，6h，9h，12h，15h，18h，21h，24h. The concentration of DMP, DMTP, DMDTP,and methomyl in rat urine were determinated and the variation of concentration wasdescribed.Results：DMP, DMTP, DMDTP, and methomyl well separated within11.2min.The retention time of DMP, DMTP, DMDTP, and methomyl (min) are:4.632,4.858,7.275,6.039. The standard addition recovery rate was greater than87.9%, and therelative standard deviation was less than8.9%. After the sample was preserved twoweeks at-20℃, the relative standard deviation was less than9.4%. The minimumdetectable concentration of DMP, DMTP, DMDTP, and methomyl were3,0.30,4,0.4 μ g/ml respectively (S/N=3). After the intragastric administration, the concentration ofDMP, DMTP, DMDTP, and methomyl in rat urine were determinated..Conclusions：The SPE-GS/MS method for quantitative and qulitation analysis ofmethomyl and the metabolites of malathion was simple, accurate, rapid, sensitive,good repeatability. The method could be used to provide reference for the exposurelevel of malathion, methomyl, and methomyl mixed pesticide malathion for theexposed population.
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