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以被苯醚甲环唑、多菌灵及烯酰吗啉污染的铁皮石斛为研究对象,采用乙腈提取,固相分散法净化,高效液相色谱-串联质谱仪分析了3种农药在铁皮石斛鲜条及栽培基质中的残留消解动态,并检测了不同水洗时间、不同溶液浓度(氯化钠和碳酸氢钠)条件下农药残留的去除情况,通过响应面方法确定了农药最佳去除方法。结果表明:3种常用农药在不同添加水平下的回收率为78.5%~106%,相对标准偏差(RSD)为0.7%~4.5%,满足农药残留检测要求;田间试验采用推荐剂量和两倍推荐剂量处理,苯醚甲环唑在铁皮石斛鲜条和基质中的半衰期分别为3.8~3.9 d和4.1~5.6 d;多菌灵的半衰期分别为2.6 d和2.8~3.1 d;烯酰吗啉的半衰期分别为2.8~2.9 d和3.6~5.1 d。响应面法结果显示:经质量分数为5.49%的氯化钠和1.27%的碳酸氢钠混合溶液浸泡5 min后再用清水冲洗45 min,残留的苯醚甲环唑去除率最高;用5.34%的氯化钠和1.22%的碳酸氢钠混合溶液浸泡5 min后再用清水冲洗45 min,多菌灵的去除率最高;而用2.07%的氯化钠和0.80%的碳酸氢钠混合溶液浸泡5 min后再用清水冲洗59 min,烯酰吗啉的去除率最高。本研究可为铁皮石斛质量安全评价体系的建立提供基础数据。
Taking Dendrobium officinale polluted by difenoconazole, carbendazim and dimethomorph as the research object, the three kinds of pesticides were analyzed by acetonitrile extraction, solid-phase dispersion purification and high performance liquid chromatography-tandem mass spectrometry Fresh residue and culture medium. The removal of pesticide residues under different washing time and different solution concentration (sodium chloride and sodium bicarbonate) was also tested. The optimum removal of pesticides was determined by response surface methodology. The results showed that the recoveries of three commonly used pesticides were 78.5% -106% and the relative standard deviations (RSDs) were 0.7% -4.5%, which met the requirements of pesticide residue detection. The recommended dose and twice the recommended The half-lives of difenoconazole in fresh shoots and matrix of D. officinale were 3.8-3.9 d and 4.1-5.6 d, respectively. The half-lives of carbendazim were 2.6 d and 2.8-3 d, respectively. The half-lives were 2.8 ~ 2.9 days and 3.6 ~ 5.1 days respectively. The results of response surface methodology showed that the remnant of difenoconazole was the highest after the soaking of 5.49% sodium chloride and 1.27% sodium bicarbonate solution for 5 min followed by rinsing with clear water for 45 min, Of sodium chloride and 1.22% sodium bicarbonate mixed solution for 5 min and then rinsed with water for 45 min, the highest removal rate of carbendazim; with 2.07% sodium chloride and 0.80% sodium bicarbonate mixed solution soaked After 5 min and then rinse with water for 59 min, the dimethoylmorpholine removal rate was the highest. This study can provide the basic data for establishing the quality safety evaluation system of D. officinale.