Determination Of Multi Pesticide Residues By Gas Chromatography Tandem Mass Spectrometry

With the widespread use of pesticides, the food contamination was serious. People pay more attention to food safety. Animal origin foodstuff was contaminated in the form of cumulated pesticides residues because they eat the polluted plants. This article established determination method of pesticide residues rapidly in fat based on reference documents in response to food safety on Pesticide Residues in fat of technology requirements.Chapter one discussed the pretreatment and analytical technology of muti-pesticides residues in samples, the max residue limits of pesticide residues in fat samples and the analytical techniques of fatty samples.Chapter two developed a novel method for the simultaneous determination of 164 pesticide residues in animal fat using gas chromatography-tandem mass spectrometry (GC-MS-MS),by conditions of gel permeation chromatography, gas chromatography-tandem mass spectrometry characteristic, the extraction solvent, the extraction method and purification mode. The target analytes were extracted with 35 mL acetonitrile for twice and concentrated to 1 mL in 45℃water bath with a rotary evaporator. The internal standard was added to the concentrated extracts, which was then filtered by 0.45μm millipore filters. Then the solution was transferred to a 10 mL volumetric flask with cyclohexane-ethyl acetate(1:1, V/V)and purified on line by gel permeation chromatography. The sample solution was determined by GC-MS-MS in multiple reaction monitoring mode. The established method showed satisfactory linearity with correlation coefficient of 0.9438 - 1.0000, among which 93.9% were above 0.9900. Under optimized conditions, the detection limits (S/N≥3) were in the range of 0.09μg/kg - 360.00μg/kg, among which 73.8% were below 10.00μg/kg. Among 164 targeted pesticides, 150 pesticides could be determined quantitatively, the average spiked recoveries of which were between 70% and 120% and the relative standard deviations of which were below 20%, indicating that the method is selective, accurate and suitable for simultaneous quantitation of 150 pesticide residues in animal fat.