Study On Determination For Multi-Pesticides Residues Utilizing Matrix Solid Phase Dispersion (MSPD) And Gas Chromatography Mass Spectrometry (GC-MS)

People pay more attention to pesticides residue on vegetables and harm on health and Environment. Many countries have established residue monitoring system and MRLs of pesticides on vegetables, so vegetables export of our country are facing more and more technical barriers. This paper studied extraction, purification and GC-MS detection conditions of pesticide residues and developed a new analytical procedure based on MSPD coupled to GC-MS for the determination of 249 pesticides in vegetables.The method was successfully used in detecting the vegetables in the market. The main results were as follows:1 In this research, we optimized the column tempreture and established GC-MS detection method for 249 pesticides. Linear regression in the concentration range of 0.05~1 mg/L (>0.99) was fine and the detection limit was 0.5~28.8μg/kg which was lower than MRLs.2 In this research, we optimized the asorbent, eluent and the rate of sample and asorbent, established a preparation method which used 2 g C18 as absorbent, GCB as purificant, 30 mL hexane:acetone(1:1) as eluent and the rate of sample and absorbent was 1:2. The recovery range was 70~130% of 221 pesticides and 28 out of the range and the relative standard deviations is below 20%.3 Samples was collected from local markets and detected using the established method. 7 pesticides (Chlorpyrifos, Metalaxyl, Carbendazim, Dipterex, Cypermethrin, Fenvalerate and Chlorothalonil) were detected in four vegetables and the contents of the 7 pesticides was lower than MRLs. Chlorpyrifos on spinach and cucumber exceeded the standard(0.01 mg/kg)of Positive List System of Japan.