Study On Multiresidue Analysis Of Organophophorus Pesticides In Rapeseed

The conditions of extraction, separation, purification and chromatography of organic phosphorus in rapeseed were studied. The method of detecting the multi-residue of organic phosphorus in rapeseed by using gas chromatography was established. It had important effect on the national residue criterion system establishment of the organic phosphorus in rapeseed. It could improve the international trade and the levels of national rapeseeds' qualities and safeties.It was studied on the factors which influenced the extraction way, extraction time and purification. The factors included the type of extractant, the amount and the extraction times, the type of purified column, the type and dosage of eluviatant about the pre-treatment of the samples. The extraction was 3 minutes (13500rpm) of high speed homogenize extraction. 50mL acetonitrile as an extractant was acted on one time extraction. The florin silicon column was taken as the purified column. The extraction was eluted by 30ml 3:2 acetone - hexane and concentrated by nitrogen blowing under 50 °C water bath.The chromatographic separated conditions were studied applied the Agilent 6890 gas chromatographic apparatus (FPD) and DB-17 capillary column(30m×0.25mm×0.25μm).The condition of chromatographic separated: the temperature of injection was 230°C, the temperature of detector was 250°C,the initial temperature was 110°Cand heated 15°C per minute till 260°C. Holding 7 minutes on 260°C and ran 3 minutes on 270°C .The flow rate of H₂, air, N₂ was 75 mL.min^-1,100 mL.min^-1,1.5 mL.min^-1, respectively.The methodology research of the multi-residue of organic phosphorus in rapeseed was carried on. 7 kinds of pesticides included phorates, methyl parathion, chlorpyrifos, isofenphos methyl, monocrotophos, parathion and acephate were added to the rapeseed on the concentration of 0.1mg/kg, 0.5 mg/kg, 1.0mg/kg respectively. The recovery ratio was in the range of 89.7%⁹8.5% and the relative standard deviation of 3 times repetition was 3.4%⁵.3%. The repetition, reproducibility and added standard recovery were accorded with the national pesticide residue criterion.Five kinds of organic phosphorus pesticides including acephate, dimethoate, parathion-methy, chlorpyrifos and parathion were spurted on the stage of stem elongate, bud flower time and the end flowering time respectively. The results indicated that detectable pesticides included acephate 0.37 mg.kg^-1, dimethoate 0.24 mg.kg^-1, parathion-methy 0.01 mg.kg^-1, chlorpyrifos 0.12 mg.kg^-1, parathion 0.98 mg.kg^-1 when spurted one times every stage respectively..The application on the rapeseed samples by the method of the multi-residue of organic phosphorus pesticides was shown that detectable rate was 7% of the total 101 rapeseeds samples. The detectable organic phosphorus pesticides included phorate, methyl parathion, dimethoate and chlorpyrifos.