Determining rest concentration of Diazinon in agriculture products (melon and cucumber) with GC-NPD and GC-MS methods

Introduction: diazinon is a moderately toxic broad-spectrum organophosphate, with a ld50 of 350 to 400 mg/kg for humans. diazinon is absorbed through the skin and gastrointestinal tract and is rapidly metabolized within a few hours. diazinon residues in melons and cucumbers have recently became a major health concern in iran. thus we decided to investigate diazinon levels in melon and cucumbers. method and materials: twenty cucumbers and 30 melons were randomly purchased from the market in mashhad. the extraction procedure was in hr- p columns precondition with methanol and water. the subsequent elution of diazinon was accomplished by a mixture of hexane-ethyl acetate (1:1, v/v) prior to determination by gc-npd and gc-ms/ms. standards were prepared spiking blank juice samples to contract the observed matrix effect. results: mean recovery rate for diazinon was 95.4% with relative standard deviation lower than %9 in a concentration range of 5-200ng/ml. mean and sd of diazinon in melons was 107.64±38.5 ng/kg. diazinon was not detected in cucumber samples. it was later confirmed that diazinon was not used for the crops of these cucumbers. conclutions: gc-npd and ms/ms was developed to determine residues of diazinon in melons and cucumbers. the gc-ms/ms analytical method showed a high efficacy for determination of dizinon residues in the fruits.