Residuesanddissipationdynamicsofflumioxazininsoybeanandsoilsamples

The residue and disspation dynamics of flumioxazin in soybean and soil were investigated by QuEChERS-high performance liquid chromatography-tandem mass spectrometry (QuEChERS- HPLC-MS/MS) method. This study was conducted in three fields including Dezhou in Shandong, Harbin in Heilongjiang and Haicheng in Liaoning for two years. The intra-day average recoveries of flumioxazin in spiked samples with fortified level of 0.000 3, 0.01 and 0.1 mg/kg were between 89% to 112% and the relative standard deviation ranged from 1.3% to 5.3% (n = 5). The inter-day average recoveries ranged from 85% to 110% and the relative standard deviation ranged from 0.4% to 4.8% (n = 15). The quantitative limits (LOQ) for soybean plant, green soybean, soybean and soil samples were 0.000 3 mg/kg which can meet the requirement of max residue limits of flumioxazin. The dissipation dynamics of flumioxazin in soybean plant and soil fitted the first order kinetics equations, and the dissipation half-lives in the soybean plant and soil were 5.8-11.8 d and 15.8-24.8 d, respectively. When flamioxazin was sprayed to soil once with the application rate of 60 and 90 g (a.i.)/hm², the final residue of flumioxazin in the soybean plant, green soybean, soybean and soil was, at harvest time, lower than the maximum residue limit of flumioxazin in soybean of China National Standard (0.02 mg/kg).