氟唑磺隆、甲基二磺隆、炔草酯和炔草酸在小麦中的残留分析

以QuEChERS前处理方法为基础，采用高效液相色谱-串联质谱(HPLC-MS/MS)检测技术，建立了除草剂氟唑磺隆、甲基二磺隆、炔草酯及其代谢物炔草酸4种化合物在小麦中残留的分析方法。麦粒样品中加入5 mL体积分数为0.1%的甲酸水溶液后，以10 mL乙腈提取，用50 mg C₁₈与100 mg 无水硫酸镁净化；麦秆样品中加入10 mL体积分数为2%的甲酸水溶液后，以10 mL乙腈提取，用100 mg C₁₈与200 mg无水硫酸镁净化。结果表明:氟唑磺隆在0.005、0.01和0.1 mg/kg，甲基二磺隆在0.01、0.02和0.1 mg/kg，炔草酯和炔草酸在0.05、0.1和0.5 mg/kg添加水平下，4种化合物在麦粒中的回收率在76%~97%之间，在麦秆中的回收率在83%~102%之间，相对标准偏差均小于10%，r > 0.99。4种化合物在麦粒和麦秆中的定量限分别为:氟唑磺隆0.005 mg/kg，甲基二磺隆0.01 mg/kg，炔草酯和炔草酸均为0.05 mg/kg。该方法可满足小麦样品中4种化合物的残留分析要求。

Residue analysis of flucarbazone-sodium, mesosulfuron-methyl, clodinafop-propargyl and clodinafop in wheat

A modified QuEChERS method was developed and validated for the determination of flucarbazone-sodium, mesosulfuron-methyl, clodinafop-propargyl and clodinafop in wheat kernel and straw by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). The wheat kernel was extracted with 10 mL acetonitrile, after 5 mL 0.1% formic acid solution was added to improve the extraction efficiency. Samples were cleaned up by 50 mg C₁₈ and 100 mg anhydrous MgSO₄. After adding 10 mL 2% formic acid solution, the wheat straw was extracted with 10 mL acetonitrile. 100 mg C₁₈ and 200 mg anhydrous MgSO₄ were used to clean up the samples. The average recoveries of four compounds in wheat kernel and wheat straw were 76%-97% and 83%-102%, respectively, with the relative standard deviations (RSDs) for those four compounds less than 10%. Good linearity was achieved with determination coefficients higher than 0.99. The limit of quantity (LOQ) is 0.005 mg/kg for flucarbazone-sodium, 0.01 mg/kg for mesosulfuron-methyl, 0.05 mg/kg for clodinafop-propargyl and clodinafop. This method meets the requirements of pesticide residue analysis.