气相色谱法测定大蒜中二甲戊乐灵·乙氧氟草醚·乙草胺3种除草剂的残留

目的]研究乙氧氟草醚、二甲戊乐灵和乙草胺在大蒜植株和土壤中的残留分析方法。方法]样品经过丙酮和水混合溶液提取后,用中性氧化铝和活性炭净化,气相色谱测定。结果]乙氧氟草醚、二甲戊乐灵、乙草胺的最小检出量分别为3.0×10-12、2.0×10-12和1.5×10-12 g,最低检测质量分数分别为6×10-4、4×10-4和3×10-4 mg/kg。乙草胺在土壤、植株中的平均回收率分别为83.9%～118.1%、87.6%～117.6%,变异系数分别为5.4%～14.3%、1.6%～9.0%,乙氧氟草醚在土壤、植株中的平均回收率分别为93.4%～109.3%、75.7%～117.2%,变异系数分别为2.5%～5.4%、2.7%～13.2%,二甲戊乐灵在土壤、植株中的平均回收率分别为78.9%～106.8%8、0.7%～118.9%,变异系数分别为2.8%～5.9%4、.7%～15.8%。结论]该方法操作简便,检测结果准确可靠,前处理重复性好,速度快,可用于大蒜实际样品的日常检测。

Determination of Pendimethalin ,Oxyfluorfen and Acetochlor Residue in Garlic by GC

Objective] To study the analytical method of oxyfluorfen,pendimethalin and acetochlor residue in garlic plant and soil.Method] Samples were firstly extracted with the mixed solution of acetone and distilled water,then purified by neutral alumina and activated carbon,and at last determined by GC.Result] The minimum detection limits of oxyfluorfen,pendimethalin and acetochlor were 3.0×10-12,2.0×10-12and 1.5×10-12 g respectively,and their minimum determination concentration were 6×10-4,4×10-4 and 3×10-4 mg/kg.The average recoveries of acetochlor ranged from 83.9% to 118.1% and 87.6% to 117.6% in soil and plant,with a coefficient variation of 5.4%-14.3% and 1.6%-9.0%;The average recoveries of oxyfluorfen ranged from 93.4% to 109.3% and 75.7% to 117.2% in soil and plant,with a coefficient variation of 2.5%-5.4% and 2.7%-13.2%;The average recoveries of pendimethalin ranged from 78.9% to 106.8% and 80.7% to 118.9% in soil and plant,with a coefficient variation of 2.8%-5.9% and 4.7%-15.8%.Conclusion] The method was simple,accurate,reliable,rapid and repetitive,it could be applied to the daily determination of garlic samples.