New Method For Detection Of Pesticide Residues In Food And Environmental Samples

Today’s society food safety and environmental pollution problem is getting people’s attention, a lot of pesticide residues caused by the use of pesticides is one of the main factors threatening food security and cause environmental pollution, and therefore a rapid and accurate analytical methods to monitor and detection of pesticide residues become inevitable. There are two mainly affect the accuracy of the results in pesticide residue analysis, first, the extraction efficiency of the sample to be tested; second, the accuracy of detection equipment and sensitivity. This paper mainly studied in a fast, simple, high pre-treatment sample extraction method and optimized conditions for gel permeation chromatography- gas chromatography / mass spectrometry(GPC-GC/MS), establishment an accurate and efficient detection method for pesticide residues of highly pigmented, high acidity and high sugar substances in foods and dust, soil in environments. The main research contents and results are as follows:1. Studied a new sample pretreatment methods, it’s combine the advantages of solid phase extraction and matrix solid-phase dispersion extraction. According to the characteristics peppers, oranges and honey, were selected acetonitrile extracted peppers, ethyl acetated oranges and honey, extraction times are 2 min, except honey need a water bath at 40℃, the peppers and orange extract at room temperature, then pH control between 6 and 7, a cleaning agent selected for pepper: PSA, GCB, and C18 each 50 mg, orange: GCB, PSA each 50 mg, honey: 100 mg PSA +50 mg GCB +100 mg C18. After extracted the three samples detected pesticide residues obtained recoveries were all between 95.6% ~ 118.9%. In addition, when considering the impact of matrix effects, matrix interference effects found in oranges is very serious, in the extraction and recovery rate of more than 180%, so the choice of the sample matrix liquid configured standard solution standard curve to obtain accurate results.2. For environmental samples dust and soil, the main research method for high-throughput processing of samples per unit time, using acetonitrile as the extraction agent, dust added 50 mg GCB, PSA and C18 each 100 mg added soil, extraction time 2 min, and the two samples were carried out using only centrifugal separation step, saving analysis time, obtained the recovery of 18 kinds of organochlorine in dust were 78.6% ~ 117.3%, 16 kinds of organicphosphorus in soil were 78.9% ~ 116.7%.3. This paper used GPC-GC/MS instrument for testing, the main role of GPC is separated from impurities and objectives of pesticides, use chinomethionate and fluvalinate to locate separation, select the peak time of fluvalinate at 3.316 min then switched test solution into the GC / MS detection, GPC conditions: the mobile phase acetone: cyclohexane(v / v, 3:7), the column temperature was 40℃and the injection volume was 10 μL. GC / MS conditions are selected to establish SIM method using the SCAN mode after a full scan of the qualitative standard pesticide scan, then quantitative analysis of samples. By optimized conditions measured of five samples in this article, obtained results were: the limit of detection 1.6 μg/Kg ~ 14.6 μg/Kg, the limit of quantification 5.3 μg/Kg ~ 48.7 μg/Kg, and the relative standard deviation 1.3% ~ 14.5%.