Dynamic Study On Residue And Digestion Of 6% Trichlorfon And Phoxim Granules In Tobacco

In this work, we established an ultra high performance liquid chromatography(UPLC) method for the determination of the amount of trichlorphon and phoxim residue in tobacco matrix. The degradation dynamics and final residues of trichlorphon and phoxim in tobacco were studied. Theoretical basis for safely use of trichlorfon and phoxim’s, and residue detection in tobacco was provided.The soil sample was solvent and extracted by dichloromethane, and ultrasound and centrifugal two times last detection; Trichlorfon in tobacco, trichlorfon and phoxim in tobacco powder were dissolved in etherand extracted by petroleum, the subject to homogenate, centrifugation(two times) and detection; Phoxim in tobacco was dissolved and extracted by petroleum, then ultrasonic and filter two times and detection. The calibration curve of dichlorvos showed good linearity from 0.089~44.90 μg/mL with the correlation coefficient were 0.9999. The average recoveries of dichlorvos were 75.22%~99.46% for soil, tobacco and tobacco powder when the fortified concentration levels were 0.01~5.00 mg/kg with the relative standard deviations less than 7.46%. The calibration curve of phoxim showed good linearity from 0.0481~24.05 μg/mL with the correlation coefficient were 0.9999. The average recoveries of phoxim were 72.10%~103.6% for soil, tobacco and tobacco powder when the fortified concentration levels were 0.005~2.5 mg/kg with the relative standard deviations less than 6.18%.Trichlorfon phoxim can be separated from their corresponding impurities near the 4.2 and 10.2 min, respectively.Field residue trials of 6% trichlorfon · phoxim granules tobacco and soil were carried out in Baijin town in Huishui Country, Guizhou Province and Dongan township in Changsha city, Hunan province during 2013 and 2014, and detected residues of trichlorfon · phoxim in soil, tobacco and tobacco powder. The results showed that the dosage of 4250 g a.i/ha and spraying 1 times and sampling in inharvest period, the residues of trichlorfon in tobacco powder <1.06 mg/kg, residues of phoxim in tobacco powder <0.32 mg/kg.The result of trichlorfon and phoxim degradation in different soils showed that the higher humidity, temperature and pH in soil, the faster speed of trichlorfon and phoxim degrade in the soil. The microorganism can promote the degration of trichlorfon and phoxim. In a word, the speed of trichlorfon and phoxim degradation in soil is mainly influenced by pH.