QuEChERS-碱水解-超高效液相色谱-串联质谱法测定青大豆、大豆和大豆油中乙草胺、异丙甲草胺及异丙草胺残留

Determination of acetochlor, metolachlor and propisochlor residues in green soybeans, soybeans and soybean oil by QuEChERS-alkaline hydrolysis-ultra performance liquid chromatography-tandem mass spectrometry

中文关键词:  氯乙酰苯胺类除草剂  2-甲基-6-乙基苯胺（EMA）  QuEChERS  液相色谱-串联质谱法

英文关键词:chloroacetanilide herbicides  2-methyl-6-ethylaniline  QuEChERS  ultra performance liquid chromatography-tandem mass spectrometry

中文摘要:

      目的 建立青大豆、大豆和大豆油中乙草胺、异丙甲草胺及异丙草胺残留的测定方法, 并探讨同类结构化合物对乙草胺以代谢物计定量的干扰。方法 采用QuEChERS前处理结合超高效液相色谱-串联质谱法测定3种母体化合物残留。并在同一提取液基础上引入碱水解和液液分配萃取, 以2-甲基-6-乙基苯胺(2-methyl-6-ethylaniline, EMA)为指示物建立水解转化分析策略, 系统考察水解及净化条件。结果 3种母体农药及EMA在相应浓度范围内线性良好, 平均回收率为77.8%~106.6%, 定量限均为0.02 mg/kg。异丙甲草胺和异丙草胺在碱性加热条件下均可转化生成EMA, 可对乙草胺以EMA计的定量结果产生干扰。结论 本方法可满足青大豆、大豆和大豆油中乙草胺、异丙甲草胺及异丙草胺母体残留和水解产物EMA检测的正确度、精密度和灵敏度要求。

英文摘要:

      Objective To establish a method for the determination of acetochlor, metolachlor and propisochlor residues in green soybeans, soybeans and soybean oil, and to investigate the interference of structurally related compounds on the quantification of acetochlor quantified as its metabolites. Methods Residues of the 3 kinds of parent herbicides were determined by QuEChERS pretreatment combined with ultra performance liquid chromatography-tandem mass spectrometry. On the basis of the same extract, alkaline hydrolysis and liquid-liquid extraction procedures were introduced, and an analytical strategy for hydrolytic conversion was established using 2-methyl-6-ethylaniline (EMA) as an indicator, with systematic optimization of hydrolysis and cleanup conditions. Results Good linearity was obtained for the 3 kinds of parent pesticides and EMA within the corresponding concentration ranges. The average recoveries ranged from 77.8% to 106.6%, and the limits of quantitation were all 0.02 mg/kg. Metolachlor and propisochlor could both be converted to EMA under alkaline heating conditions, thereby interfering with the quantification of acetochlor expressed as EMA. Conclusion This method can meet the requirements for accuracy, precision and sensitivity in the determination of parent residues of acetochlor, metolachlor and propisochlor, as well as the hydrolysis product EMA, in green soybeans, soybeans and soybean oil.