Determination Of46Pesticide Residues In Peanut Using Gel Permeation Chromatography And Gas Chromatography/Mass Spectrometry

The presence of pesticide residues in food is crucial to human’s life. It is one of the most seriousproblems concerning food safety that has attracted great attention of related governments andorganizations. Peanut is an important crop in the north of the economy, in order to improve the output ofpeanut, pesticides are used in peanut to protect the plants from damage and infestation by insects andpathogens. Then pesticide residue caused serious pollution and was a serious health risk. Thereforemonitoring of pesticide residues in peanuts is becoming more and more stricter, many countries haveestablished residue monitoring system and MRLs of pesticides in peanut, so that peanut export of ourcountry is facing more and more technical barriers. This paper studied the conditions of extraction,purification and GC-MS detection conditions of pesticide residues and developed a new analyticalprocedure based on SPE coupled to GPC-GC-MS for the determination of46pesticides in peanut. Themain results were as follows:1. We first optimized the conditions of chromatography and mass spectrometry ofselected46kinds of pesticides including organochlorines, organophosphates, and herbicides,chose the suitable temperature programming and selected ions, and then successfully established aGC-MS detection method for the target. The MS condition was that DB-5MS capillary column and theoven temperature was started at82°C and held for4.5min; then increased to300°C at a rate of8°C/min, and was held for4.25min. The suitable GPC collection time was3.51-5.51min. And theselected ions used for identification and quantitation were shown in Table1. In the optimizedchromatogram and MS condition,46pesticides were separated well and correlationcoefficients were greater than0.99for concentrations from0.02to1.0mg/L.2. We used SPE as pretreatment technique and GC-MS as detection technique for multiresidueanalysis of pesticides in peanut. In pretreatment steps, we optimized five aspects including the type ofextraction solvent, extraction time, SPE column, the type and volume of elution solvent. And thedeterminated SPE sample preparation method was that the sample was extracted with50mL acetonitrilefor25min, then was purified by NH2column and eluted by20mL acetonitrile, and diluted in2mLacetone after the elution solvent was evaporated to dryness and injected into the GC-MS system. Therecovery range was70-130%of43pesticides and RSDs20%were obtained for samples fortifiedat0.02,0.05, and0.1mg/kg (n=5). 3. The proposed method was easier, faster and high sensitivity. It had lower quantification limits,good recoveries and consumed less organic solvents in the process of preconcentration. It could meet thedemands of practical use for the rapid determination of46kinds of pesticides in peanut and coulddecrease the danger to environment and human health.