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| Analysis of Residual Profiles of Pymetrozine and Isoprocarb SC in Paddy Field by QuEChERS Combined with UPLC-ESI-MS/MS |
| Received:January 29, 2014 |
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| KeyWord:pymetrozine;isoprocarb;paddy soil;residual deposition;persistence;UPLC-ESI-MS/MS |
| Author Name | Affiliation | E-mail | | WANG Quan-sheng | Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310029, China | | | CAO Meng-chao | Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310029, China | | | LIU Ya-nan | Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310029, China | | | WEI Peng | Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310029, China | | | ZHU Guo-nian | Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310029, China | | | WANG Meng-cen | Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310029, China | wmctz@zju.edu.cn |
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| Abstract: |
| In this work, a rapid, accurate and sensitive method for determining the residues of pymetrozine and isoprocarb by UPLC-ESI-MS/MS combined modified-QuEChERS was developed, and was then applied to investigate the residual deposition and persistence of pymetrozine and isoprocarb SC in paddy soils under field conditions. The reliability of the method was evaluated by extracting the pesticide-free paddy samples spiked with authentic pesticides at various concentrations with acetonitrile, and purifying the extracts by salting-out and then analyzing pesticides by UPLC-ESI-MS/MS combined with external standard method. The recovery percentages of the pesticides ranged from 75.2% to 115.9% with the relative standard deviation(RSD) from 2.6% to 19.1%. The limit of quantification(LOQ) of both pesticides was 0.001 mg·kg-1 in paddy field water and 0.005 mg·kg-1 in rice-plant/soil, respectively, indicating that this method could be used to determine the trace amount of residual pymetrozine and isoprocarb in paddy field. In the field trial, the degradation curves of the pesticides fit the first-order kinetics. The half-life was 0.7~12.6 days for pymetrozine and 0.4~5.2 days for isoprocarb, suggesting that both pesticides were easily degradable compounds in the environment. In contrast to its WG-formulation, pymetrozine and isoprocarb SC showed relatively high dissipation rates in plant tissue, but relatively low in soil, showing the profound influence of formulation type of pesticides on their persistence in the agricultural ecosystem. |
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