Study On Detection Methods Of Three Kinds Of Pesticide Residues In Drinking Water By UPLC-MS/MS

Ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) with high sensitivity, good selectivity and high stability has become the first choice for the simultaneous detection of pesticide multiresidues. Graphite nanomaterials with its excellent performance and good specific activity, expected to become effective pre-treatment enriched material. Chemical pesticides that are commonly used in recent years in China were selected as material in this study (sulfonylurea herbicides, triazole fungicides and neonicotinoid insecticides). By combining with micro solid phase extraction technology, we developed the method of detecting this three kinds of pesticide residues by UPLC-MS/MS. The main research contents are summarized as following:1. The establishment of a method for simultaneous determination of 11 sulfonylurea herbicides in drinking water by UPLC-MS/MS. Water samples were filtered by 0.22μm membrane, detected under optimized chromatographic condition and ESI+ scanning and multiple reaction monitoring (MRM) mode, quantified by external standard method. 11 sulfonylurea herbicides presented a good linearity in the range of 5-200 μg/L(r> 0.995). The limits of detection (LODs) were 0.06μg/L-0.46 μg/L. The rates of recovery for the spiked samples ranged from 85.6%-102.1% and the relative standard deviations (RSDs) were below 9.4%. In this study, drinking water samples were only filtered by 0.22μm membrane, thus to have the experimental procedure simplified. The method was simple, rapid, sensitive and accurate, and can be used for the detection of sulfonylurea herbicides in drinking water.2. The establishment of a method for simultaneous determination of 6 triazole fungicides in drinking water by UPLC-MS/MS. Water samples were filtered by 0.22μm membrane, detected under optimized chromatographic condition and ESI+ scanning and multiple reaction monitoring (MRM) mode, quantified by external standard method. The regression equation of 6 triazole fungicides was fitted well in the linear range of 1-200 μg/L, the correlation coefficient was over 0.999. The LODs were between 0.017 and 0.035 μg/L, the average recovery rate ranged from 89.5% to 104.5%, and the RSDs were below 8.5%. In this study, drinking water samples were only filtered by 0.22μm filter processing to let the experiment becomes simple, fast, sensitive and accurate, and had good precision. It was suitable for the detection of triazole fungicides in drinking water.3. Use closed oxidation process to synthetize graphite oxide, ultrasonic dispersion method to obtain the graphene oxide aqueous solution and glutaraldehyde crosslinking method to prepare chitosan supported graphene oxide film (CCTS-GO). Optimized conditions of preparation and characterized the materials by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The result showed that GO was successfully immobilized on the CCTS film.4. Combining CCTS-GO film micro solid phase extraction with UPLC-MS/MS, to establish a method for simultaneous determination of 5 neonicotinoid insecticides in drinking water. Optimized micro solid phase extraction and chromatographic conditions, water samples were detected by MRM mode under the condition of ESI+ scanning and quantified by external standard method.5 neonicotinoid insecticides presented a good linearity in the range of 0.2-200 μg/L(r>0.994). The LODs were below 0.07 μg/L. The rates of recovery for the spiked samples ranged from 71.6% to 101.5% and the RSDs were below 9.8%. Its accuracy and sensitivity could be satisfied with the determination of neonicotinoid pesticides in drinking water samples.