丙硫咪唑在烟草中的残留及消解动态

为明确丙硫咪唑在烟草中的残留消解规律，制定科学合理的农药残留限量标准，采用QuEChERS与高效液相色谱-串联三重四极杆质谱 (HPLC-MS/MS) 联用技术检测了烟草中丙硫咪唑的残留量，并进行了实际样品检测。结果表明:在0.001~1 mg/L范围内，丙硫咪唑的质量浓度与对应的峰面积间线性关系良好，R2 > 0.998。在0.02、0.2和2 mg/kg 3个添加水平下，丙硫咪唑在鲜烟叶中的回收率为94%~97%，相对标准偏差 (RSD) 为1.2%~2.7%；在0.01、0.1和2 mg/kg 3个添加水平下，丙硫咪唑在干烟叶中的回收率为85%~104%，RSD为2.0%~8.1%。丙硫咪唑在干烟叶和鲜烟叶中的最低检测浓度 (LOQ) 分别为0.01和0.02 mg/kg。消解动态试验结果表明，丙硫咪唑在鲜烟叶中的消解半衰期为5.4~16.1 d。以有效成分90和135 g/hm2的剂量分别施用15%丙硫唑?戊唑醇悬浮剂3次，于末次施药后7 、14和21 d时，干烟叶中丙硫咪唑的残留量分别为0.14~3.04、0.33~2.20和0.17~1.85 mg/kg。推荐其残留限量为 2 mg/kg，按照农药合理准则规范使用农药，于末次施药后21 d，丙硫咪唑在干烟叶中的残留量小于2 mg/kg，残留风险水平较低。

Residue and dissipation dynamic of albendazole in tobacco

To investigate the residue and dissipation of albendazole in tobacco and provide reference for the setting of maximum residue limit (MRL), an analytical method and a good agricultural practices (GAP) experiment of albendazole residues in tobacco were established and had been tested for samples by using QuEChERS and high performance liquid chromatography-tandem triple quadrupole mass spectrometry (HPLC-MS/MS). Good linearity between the mass concentration of albendazole and the corresponding peak area was achieved from 0.001 to 1 mg/L, with a coefficient of determination higher than 0.998. At three addition levels of 0.02, 0.2 and 2 mg/kg, the recoveries of albendazole in fresh tobacco leaves ranged from 94% to 97%, with the relative standard deviation (RSD) was 1.2%-2.7%. At three addition levels of 0.01, 0.1 and 2 mg/kg, the recovery of albendazole in cured tobacco leaves were 85%-104%, with the RSD was 2.0%-8.1%. If the lowest spiked concentration was recognized as the limit of quantitation (LOQ), the LOQs of albendazole in cured tobacco leaves and fresh tobacco leaves were 0.01 and 0.02 mg/kg, respectively. The dissipation and terminal residue levels of albendazole in tobacco demonstrated that the half-life of albendazole in fresh tobacco leaves was 5.4 to 16.1 days. When sprayed at 90 and 135 g a.i./hm² for three times, the terminal residues of albendazole in cured tobacco leaves at the pre-harvest interval of 7, 14 and 21 days were 0.14-3.04 mg/kg, 0.33-2.20 mg/kg and 0.17-1.85 mg/kg, respectively. It is recommended that the MRLs should be 2 mg/kg. The pesticide should be used in accordance to the recommended dosage and application interval. 21 days after the last spray, the residue was less than 2 mg/kg, which demonstrated that the residual risk level was low.