Studies On Determination Of Pesticides Residues And Matrix Effects In Agricultural Products

Pesticide residues in agricultural products is always an important issue in food safety analysis. Strengthen research on the detection of pesticide residues, establish-ing a rapid, efficient, sensitive residue analysis method, is not only related to the health of consumers, but also related to the orderly development of imports and exports of agricultural products. A simple and rapid method was developed for the simultaneous determination of multi-pesticide residues in edible fungi by liquid chromatography tandem mass spectrometry in this paper, also the matrix effects, which impact the accuracy of the quantitative results, was studied.The main content of this thesis is as follows:1. A simple and rapid method was developed for the simultaneous determination of 80 pesticide residues in edible fungi. The sample was extracted with acetonitrile, prepared by the Qu ECh ERS(quick, easy, cheap, effective, rugged and safe) method, separated on a Waters CORTECE UPLC C18+(100×2.1 mm, 1.6μm) column, detected by HPLC-MS/MS performing on positive/negative electrospray ionization(ESI+/-) and the multiple reaction monitoring(MRM) mode. In this study, the calibration curves of 80 pesticide residues were linear in the range of 1.0-200 μg/L with correlation coefficients more than 0.9936. The recoveries for 95% compounds at the fortified levels of 10, 20 and 100 μg/Kg ranged from 80% to 120% with the relative standard deviations(RSD) below 13%. The limits of quantitation(LOQs,S/N≥10) for 80% of pesticides were less than 4.0 μg/Kg. The method is highly efficient, sensitive and suitable for the determination of multi-pesticide residues in edible fungi.2. Matrix effects and its influencing factors in determination of pesticide residues in edible fungi by HPLC-MS/MS were studied. The capabilities to eliminate matrix components of different clean-up methods, the diversity of fungi and pesticides, the dilution method compensation for matrix effects were evaluated. According to the evaluating method of matrix effect, Qu ECh ERS purification was demonstrated to be enough to eliminate most of the matrix effect. We found that matrix effects were influenced by sample matrix, the varieties and concentrations of pesticide. A dilution procedure demonstrated to be enough to eliminate most of the matrix effects.3. In this section, the relative matrix effects in determination of pesticide residues in sorts of vegetable by HPLC-MS/MS were studied. 45 pesticides, such as organophosphorus, benzene and carbamate, were collected. The sample was extracted with acetonitrile, prepared by the Qu ECh ERS method. The relative matrix effects of samples with different vegetables were evaluated by the recovery. Results indicated that most pesticides show stronger matrix effects in onion and garlic, such as methamidophos, carbary, phorat-sulfoxide ect. Certain pesticide are matrix dependent such as admire, aldicarb, aldicarb, carbary ect. The research provided reference for the rapid and accurate determination of pesticides residue in vegetables by LC-MS/MS.