Residue Analysis And Digestion Dynamics Study Of 32% Biphenyl·thiazosin Suspension On Tobacco

In current work, we developed a liquid chromatography coupled with tandem mass spectrometry(LC-MS/MS) method to determine the dimethomorph residue of 32% bifenthrin?thiamethoxam(suspension concentrate, SC) in tobacco matrix.Bifenthrin and thiamethoxam in tobacco( soil and tobacco powder) samples were extracted with acetonitrile(1% formic acid) by ultrasonic, NaCl was subsequently added, after centrifugation, the supernatant was cleaned up using NH2-SPE cartridges samples, and the samples was determined by GC-ECD and LC-MS/MS. The results showed that the external standard curve showed a good linearity between 0.40-20.00 ?g/mL with the correlation coefficient of 0.99. The recoveries of Bifenthrin in tobacco were ranged from 72.95-106.0% with RSDs between 2.94-7.15%. The recoveries of Bifenthrin in soil were ranged from 88.73-95.64% with RSDs between 2.29-3.12%. The recoveries of Bifenthrin in tobacco powder were ranged from 83.99-106.3% with RSDs between 2.25-4.01%. The recoveries of thiamethoxam in tobacco were ranged from 73.10-76.90% with RSDs between 1.68-6.65%. The recoveries of thiamethoxam in soil were ranged from 91.76-108.9% with RSDs between 1.18-3.29%. The recoveries of thiamethoxam in tobacco powder were ranged from 72.27-83.37% with RSDs between 2.94-3.66%.The sensitivity, accuracy and precision of the method meet the requirements of pesticide residues analysis.The field trials of 32% bifenthrin?thiamethoxam(SC) were performed in Guizhou and Hunan province during the agricultural season in 2014 and 2015. The residues of bifenthrin and thiamethoxam in tobacco powder and soil were carried out. The results indicated that the constituents of bifenthrin and thiamethoxam are below the MRL in pepper(the MRLs of bifenthrin, and thiamethoxam were 2.5 mg/kg, and 5 mg/kg respectively).