李新国　李慧冬

摘要 [目的]采用气相色谱-质谱（GC-MS）法测定二甲戊灵在棉花和土壤中的残留及消解动态。[方法]土壤和棉籽样品经过乙腈浸泡，超声波提取，再经过净化后采用气相色谱-质谱（GC-MS）仪测定。[结果]在0.01～0.50 μg/mL，二甲戊灵的峰面积（y）与质量浓度（x）有良好的线性关系（r=0.999 2）。此方法中二甲戊灵的最低检出限为0.001 ng，添加最低检出浓度为0.01 mg/kg。在0.01～0.50 mg/kg 3个添加水平下，二甲戊灵在棉株中回收率在88.1%～102.0%，RSD为1.64%～2.87%;在土壤中回收率在91.2%～107.0%，RSD为1.62%～4.81%;在棉籽中回收率在97.4%～102.0%，RSD为1.52%～3.64%。消解曲线符合一级动力学方程，在棉株和土壤中的降解半衰期分别为1.43～5.88和5.48～11.50 d。[结论]该研究为二甲戊灵在棉花上合理使用及其MRL值的制定提供基础数据。

关键词 气相色谱-质谱法;二甲戊灵;棉株;土壤;棉籽;残留;消解动态

中图分类号 S481.8文献标识码 A文章编号 0517-6611（2020）22-0187-03

doi：10.3969/j.issn.0517-6611.2020.22.050

Residue and Digestion Dynamics of Pendimethalin in Cotton and Soil by Gas Chromatography-Mass Spectrometry Method

LI Xin-guo1，LI Hui-dong2

（1.Heze Eco-environment Monitoring Center of Shandong， Heze，Shandong 274000;2.Institute of Quality Standard and Test Technology for Agro-products， Shandong Academy of Agricultural Sciences， Jinan， Shandong 250100）

Abstract [Objective]The residue and degradation dynamics of pendimethalin in cotton and soil were determined by gas chromatography-mass spectrometry （GC-MS）method.[Method] Soil and cottonseed samples were soaked in acetonitrile， extracted by ultrasonic wave， purified and determined by phase chromatography-mass spectrometry （GC-MS）. [Result] In the range of 0.01-0.50 ug/mL， there was a good linear relationship between the peak area （y） of pendimethalin and the mass concentration （x） （r=0.999 2）. The minimum detection limit of pendimethalin by the instrument was 0.001 ng and the minimum detection concentration was 0.01 mg/kg. Under the addition levels of 0.01-0.50 mg/kg， the recovery rate of pendimethalin in cotton plants was 88.1%-102.0%， and RSD was 1.64%-2.87%;the recovery rate in soil was 91.2%-107.0%， and RSD was 1.62%-4.81%;the recovery rate in cottonseed was 97.4%-102.0% ，and RSD was 1.52%-3.64%. The degradation curve conforms to the first-order kinetic equation， and the degradation half-lives in cotton plants and soil were 1.43-5.88 and 5.48-11.5.0 d respectively.[Conclusion] This study provides basic data for the rational use of pendimethalin on cotton and the formulation of its MRL value.

Key words Gas chromatography-mass spectrometry （GC-MS）method;Pendimethalin;Cotton plant;Soil;Cottonseed;Residue;Degradation dynamics

基金項目 山东省自然科学基金项目（ZR2016Y027）。

作者简介 李新国（1979—），男，山东菏泽人，工程师，硕士，从事生态环境检测工作。*通信作者，副研究员，博士，从事农产品质量安全研究。

收稿日期 2020-05-06

二甲戊灵（pendimethalin）是旱田作物一种选择性除草剂，为选择性芽前、芽后旱田土壤处理除草剂[1]，其除草机理：杂草通过正在萌发的幼芽吸收药剂，进入植物体内的药剂与微管蛋白结合，抑制植物细胞的有丝分裂，从而造成杂草死亡[2]。二甲戊灵是一种对人畜、鸟类和蜜蜂低毒，对杂草高效的除草剂。

有关二甲戊灵的除草效果已有较多报道[3-8]，其检测方法及在农作物、土壤中的消解动态报道较少[8-9]。鉴于此，该研究采用气相色谱-质谱（GC-MS）法测定二甲戊灵在棉花和土壤中的残留及消解动态，以期为二甲戊灵在棉花上合理使用及其MRL值的制定提供基础数据。……