Research On Multi-residue Determination Of Pesticides In Oilseeds And Vegetable Oil By MSPD-GC.

Application of pesticides could almost be found in every domain of agriculture production,the hazard caused by pesticides residue have been recognized while increasing the production of agri-product.Pest- icide residue in oilseeds and vegetable oil has became a hotspot of the world and being paid more and more attentions.It was very important to avouch the safety of oilseeds and vegetable oil, because China is s major producer as well as a major consumer. However,there are backward in the determination and standard comparing with the advanced countries and organizations.Research on the technique of pesticide residues determination could have great significance on improving the quality of oil product . The most commonly used pyrethriod and organophosphorus pesticides in oil crops were focused on in this paper. Effects of absorbents,eluent and proportion of sample and filling on purification of matrix solid-phase dispersion were investigated.With the optimization of pretreatment,a method based on matrix soild-phase dispersion combined with GC for the multiresidue analysis in oilseeds and vegetable oil was developed.The method was accurate,precise and simple to use.1.In this research, matrix solid-phase dispersion method was used to extract and purify pyrethroid pesticides from oilseeds with high oil content, the main conditions of MSPD were optimized,a pretreatment method with 0.5 g aminopropyl as assistant absorbent, 1.5 g florisil as absorbent,10 mL 20% acetone/hexane as elute and the rate of sample and filling 1:3, 4 min as the rubbing time. were established Adding standard materials to blank sample of oilseed,peanut and soybean for the test of recovery, the mean recoveries were found in a range of 88.8%～110.4% with relative standard deviation less than 8.39%,the result of variance analysis showed that the method could be well used in determination of 8 pyrethroid pesticides residue in rapeseed,peanut,soybean and other oilseeds. Analysis of the 100 samples which were collected from the main rapeseed areas in China showed that the detection rate was 7%, which implies potential threat in rapeseed production.2.Matrix solid-phase dispersion method was used to extract and purify pyrethroid and organophosph- orus pesticides residue in vegetable oil, the extraction volume, extraction times and the main conditions of MSPD were optimized.A pretreatment method with 12 mL petroleum ether saturated with acetonitrile as extracting solution, florisil as absorbent and the sample and filling rate of 1:4, 3 min as the rubbing time were established.Samples of Jin long yu,Lu hua,Fu lin men,Hu ji hua,Yuan bao and so on from the domestic market were collected for pyrethroid and organophosphorus pesticides residue determination, and dimethoate was detected in soybean oil with detection rate of 1.67%.The results showed that the edible oil in domestic market were safe and the decomposition and distribution of pesticides residue.during processing from oilseeds to oil were discussed.The result of pesticides residue in the edible oil were same to the result detected by national standards.