Research On The Determination Method Of Organophosphorus Pesticides Residue In Rapeseed By MSPD-GC

The use of pesticides provides unquestionable benefits in increasing agricultural production, However, the problem of pesticide residues has potential risk to consumers. China is a big rapeseed produced country and rapeseed is the main source of edible oil and feed protein. Take some research on the technique of pesticide residues test will have some significance on the improving of oil and oil product quality and the healthy of people. The oil content of rapeseed exceed 40%, high fat content will do some harm to the column and cause signal compress. How to separate and purify pesticide residues from rapeseed is the key of the establishment of test technique. This article focus on extracting and cleaning up 14 organophosphorus pesticide residues from rapeseed, and optimizing the condition of gas chromatogram. A test method of 14 organophosphorus pesticide residues in rapeseed was established. The main results of this paper as followed:1. In this research, matrix solid-phase dispersion method was used to extract and purify pesticides from rapeseed, for the high oil content, we optimized the asorbent, elute and the materials for secondary cleaning up, established a preparation method which used 2g florisil as absorbent, 10mL acetone as elute and the rate of sample and filling was 1:4, ODS-C₁₈ and actived carbon were taken as secondary cleaning-up materials by solid dispersion cleaning up method.2. A study on the type of column and the condition of gas chromatogram was carried out in this paper, GC detection method of organophosphorus pesticide residues was established. Adding different level standard materials to blank for the test of recovery, the results showed that the recovery range was 79.9%～113.3% with relative standard deviation lower than 10% which indicated the method satisfied the demand on pesticide residue analysis. Compared with the nation method, the recoveries increased for 7.3-39.9%.3. 140 samples was collected from the main rapeseed product areas in our country for 14 organophosphorous insecticides detected using the established method., 5 organophosphorus pesticide methamidophos, phorate, chlorpyrifos, methyl parathion and dimethoate was detected in rapeseed. The detection rate respectively was 6.4%,3.6%,3.6%,2.1% and 4.2% ,which means it has potential threat in rapeseed consumption.