GC-μECD测定鲜食毛豆中苯醚甲环唑残留的研究

Determination of difenoconazole residue in fresh soy bean by GC-μECD

目的建立一种适用于基层单位测定鲜食毛豆等蔬菜中苯醚甲环唑残留的方法。方法样品切碎后,加乙腈,在高速分散均质机中均质萃取苯醚甲环唑,用氯化钠分层,有机相浓缩液用Carbon/NH2固相萃取小柱净化,丙酮二氯甲烷混合液(1+1)洗脱,浓缩后,用DB—5 30 m×320μm×0.25μm色谱柱,气相色谱-微池电子捕获检测器测定。结果苯醚甲环唑在0.05μg/ml^1.0μg/ml范围线性关系良好(r=0.9998),方法检出限为0.013μg/ml,5倍浓缩定量下限为0.0086 mg/kg,重复测定相对偏差≤10%,加标回收在86%~110%之间。结论该法具有操作简便,样品浓缩净化效果好,检出限低,加标回收高的优点,能作为基层单位用于测定苯醚甲环唑的方法。

Objective To establish an optimal analytical method for determination of difenoconazole residues in fresh soy bean at the grassroots units. Methods The sample was cut up and homogenized in a high - speed dispersive homogenizer, then ace- tonitrile was added to extract difenoconazale from the sample. After extraction and NaCI layering, the organic phase concentrated solution was enriched and purified by solid phase extraction on Carbon/NH2 column, eluted with the mixture of acetone/dichlo- romethane （ 1 ： 1, v/v）. Finally, the target component in the purified sample was detected by GC equipped with DB column （30 m x 320 μm x 0.25 μm） and micro electron capture detector. Results This method had good linear relationship with difenoconazole concentrations between 0. 05 μg/ml - 1.0 μg/ml（ r = 0. 9998）, and the limit of detection was 0. 013 μg/ml, the limit of quantitation was 0. 0086 mg/kg, the relative deviation of repeated measurement was less than or equal to 10%, and the standard recovery was between 86% - 110%. Conclusion This method has the following advantages of user - friendly control, good effects of sample enrichment and purification, low limit of detection and high standard recovery, so it is suitable for deter- mination of difenoconazole in the grassroots units.