烯效唑在棉花及土壤中的残留及消解动态

Residue and dissipation of uniconazole in Gossypium spp. and soil

建立了烯效唑在棉花叶片、棉籽和土壤中残留的高效液相色谱-串联质谱(HPLCMS/MS)检测方法,并运用该方法对烯效唑在棉花叶片和土壤中的残留消解规律进行了研究。样品用乙腈-水提取,经Cleanert NH_2固相萃取柱净化,电喷雾正离子多反应监测模式HPLCMS/MS检测,外标法定量。结果表明:烯效唑在棉花叶片、棉籽和土壤中的平均添加回收率在74%~101%之间,相对标准偏差(RSD)在1.2%~10%之间(n=5)。烯效唑在3种基质中的检出限(LOD)均为0.01 ng,定量限(LOQ)均为0.01 mg/kg。该方法准确、灵敏、简单,适用于棉花样品中烯效唑残留的检测。田间试验结果表明:烯效唑在棉花叶片和土壤中的消解半衰期分别为4.2~5.0 d及15.8~19.7 d;于收获期采样,烯效唑在棉籽和土壤中的最终残留量分别为<0.01 mg/kg和<0.022 mg/kg。

An analytical method with high performance liquid chromatography-tandem mass spectrometry （HPLC-MS/MS） was established to test uniconazole residues in Gossypium spp. leaves, Gossypium spp. seeds and soil. Uniconazole residue and dissipation on Gossypium spp. leaves and soil were also investigated with this method. Uniconazole residues were extracted with acetonitrile/water mixture and an aliquot of the extract was purified by a solid-phase extraction Cleanert NH2 cartridge. Finally, the analytes were measured by multiple reaction monitoring （MRM） in the electrospray positive ionization mode. The extemal standard method was adopted for the quantification. The results showed that the recovery rate ofuniconazole in Gossypium spp. leaves, Gossypium spp. seeds and soil were between 74%-101%, with the relative standard deviations from 1.2% to 10% （n = 5）. The limits of detection （LOD） of the method were 0.01 ng and the limits of quantification （LOQ） were 0.01 mg/kg for three matrices. The method is accurate, sensitive, simple and suitable for the determination of uniconazole residues in Gossypium spp. samples. Field experimental results showed that the dissipation half-lives of uniconazole in Gossypium spp. leaves and soil were 4.2-5.0 days and 15.8-19.7 days, respectively. The terminal residues at harvest in Gossypium spp. seeds and soil were lower than 0.01 mg/kg and 0.022 mg/kg, respectively.