| Abstract: | On the base of repetitive experiments, the gas chromatography was established on the quantitative determination of fenpropathrin residual content in vegetable soybean. Meanwhile, the degradation dynamics of Fenpropathrin in vegetable soybean were studied in the field plots,and the safe usage technology demonstration experiments were researched. On the suitability of the analysis method, the results of deterruination showed that the average recovery ranged from 94.2% to 109.1%, RSD ranged from 1.36% to 3.15%, LOD was 0.001ng, LOQ was 0.001 mg/kg. This method was simple, accurate, and it could satisfy the analysis of reality samples. It that studies on the residual degradation dynamics and safe usage technologies of fenpropathrin in vegetable soybean showed, the original sidiment quantity of fenpropathrin were much difference at different application in vegetable soybean,and the degradation rates were identical basically at different application in the same growth season. But the degradation rates were difference slightly in different growth season,the degradation rates in the early season was faster than the late season. DT50 in the early season was 4.1d and T99 was 27.1d . DT50 in the late season ranged from 4.3d to 4.5d and T99 ranged from 29.0d to 30.0d . According conventional method, vegetable soybean was sprayed once with 90.00 g/hm^2 effective dose of fenpropathrin, the last residues were less than 0.5mg/kg 15 days after applied and less than 0.1mg/kg 25 days after applied, while it was twice at 7d intervals , the last residues were less than 0.5mg/kg 18 days after the second applied and less than 0.1mg/kg 28 days after the second applied. According to GB2763-2005 and the MRL standards of Japan, the produtcs fulfiled the quality safety requirements of china and Japan. |
