Abstract

A solid-phase microextraction (SPME) coupled to gas chromatography-mass spectrometry method was validated for the simultaneous determination of penconazole, cyproconazole, epoxiconazole, deltamethrin, azoxystrobin and kresoxim-methyl in paddy rice irrigation water. Different SPME fiber coatings and pH values were tested. Polydimethylsiloxane (PDMS) and pH 7 were chosen to optimize extraction. All pesticides presented a recovery percentage between 90.5 and 104.2%; and detection and quantification limits were 0.03 and 0.05 µg/kg for azoxystrobin and cyproconazole, 0.02 and 0.05 µg/kg for deltametrhin and epoxiconazole, 0.02 and 0.03 µg/kg for kresoxim-methyl, and 0.01 and 0.02 µg/kg for penconazole. The expanded uncertainty was estimated for all pesticides showing results lower than 20%. A total of 100 paddy rice irrigation water samples, collected in different rice fields from Argentina, were evaluated. The study showed that 86 of them presented residues. The concentrations exceeded the values that were set by European legislation and the frequencies were higher than 86% so the agricultural practices should be revised.

摘要

固相微萃取-气相色谱-质谱联用验证了稻米灌溉水中戊康唑，环丙康唑，环氧苯并恶唑，溴氰菊酯，嘧菌酯和克雷索辛甲基的同时测定。测试了不同的SPME纤维涂层和pH值。选择聚二甲基硅氧烷（PDMS）和pH 7以优化提取。所有农药的回收率在90.5％至104.2％之间。嘧菌酯和环丙康唑的检出限和定量限分别为0.03和0.05 µg / kg，溴氰菊酯和epoxiconazole的检出限为0.02和0.05 µg / kg，克雷索辛甲基的检出限为0.02和0.03 µg / kg，戊康唑为0.01和0.02 µg / kg。估计所有农药的不确定性扩大，结果低于20％。共有100个水稻灌溉水样，评估了从阿根廷不同稻田收集的烟叶。研究表明其中有86种残留物。浓度超过了欧洲法规所设定的值，且频率高于86％，因此应修改农业实践。