The use of experimental design for optimisation of QuEChERS extraction of commonly used pesticides in Egyptian soil and drainage water and their determination by GC/MS

In this study, a Quick, Easy, Cheap, Effective, Rugged and Safe method (QuEChERS) method was optimised to extract 30 pesticides which are the most used in Egypt in soil and drainage water. Optimisation was performed by Experimental Design expert 7.1 to get better recoveries. The procedure combined with a developed GC-MS for determination of these pesticides. Total analysis time was 36 min with 1 ml injection volume. The limit of quantification (LOQ) was ranged between 4.59 ng/ml, and 15.91 ng/ml for all pesticides. Most standard deviations were in the range between 0.41 and 1.41 indicating satisfactory accuracy. The validated method was applied to Egyptian soil and drainage water samples brought from different places in Damietta city. Dimethoate, β-Endosulfan, DDD, Malathion, Vinclozolin, DDT, Endrin, Cyprodinil, Primiphos ethyl, Tetradifon, Parathion ethyl and Diazinon were detected and quantified. So risk assessment on human health should be considered especially for those pesticides.

本研究针对埃及土壤与排水水中最常使用的30种农药，优化了一种快速、简便、低成本、高效、稳定且安全的QuEChERS（Quick, Easy, Cheap, Effective, Rugged and Safe）前处理方法。本研究采用Design-Expert 7.1实验设计软件开展方法优化，以获得更优异的回收率。将该前处理流程与自研的气相色谱-质谱联用（GC-MS）检测方法结合，实现上述农药的定性定量分析。整个分析流程总时长为36分钟，进样体积为1 mL。所有目标农药的定量限（limit of quantification, LOQ）介于4.59 ng/ml至15.91 ng/ml之间。多数农药的标准偏差处于0.41至1.41范围内，表明该方法具有令人满意的准确度。将该经方法学验证的分析方法应用于从埃及达米埃塔市不同区域采集的土壤与排水水样品。本次检测共检出并定量了乐果（Dimethoate）、β-硫丹（β-Endosulfan）、DDD、马拉硫磷（Malathion）、乙烯菌核利（Vinclozolin）、滴滴涕（DDT）、异狄氏剂（Endrin）、嘧菌环胺（Cyprodinil）、乙基保棉磷（Primiphos ethyl）、四氯杀螨砜（Tetradifon）、乙基对硫磷（Parathion ethyl）以及二嗪磷（Diazinon）。因此，需针对上述农药开展人体健康风险评估工作。