小麦子粒中五种有机磷农药多残留分析方法研究

Detection of 5 Organophosphorus Pesticide Residues in Wheat Grain

采用索氏提取法和溶剂提取法对小麦子粒中的甲胺磷、乙酰甲胺磷、乐果、甲基对硫磷、马拉硫磷进行前处理,采用SUBTM-5型毛细管柱、NPD(Ni63)在优化的气相色谱条件下,对添加的5种农药的标准样品进行检测,结果显示,方法的平均回收率均在75.0%以上,相对标准偏差为3.52%～9.74%,最低检测限分别是0.001 2 mg.kg-1,0.001 9 mg.kg-1,0.002 6 mg.kg-1,0.003 1 mg.kg-1和0.004 4 mg.kg-1。同时,确立了以氧化乐果为内标物的样品定量分析方法,内标物氧化乐果在0.05～3.20 mg.L-1浓度范围内线性回归方程为y=17.743 6x+1.274 9,R2=0.989 8。本方法准确、简便、重现性好。采用同样的试验方法还获取了所采3个批次实际样本的残留结果。

The residue of Methamidophos,Acephate,Dimethoate,Parathionmethyl and Malathion in wheat grains were ex-tracted and purified by Soxhlet and solvent extraction.The prepared analytical samples were analyzed by GC-NPD（Ni63） on the optimized chromatographic conditions with SUBTM-5 column.The results showed that the average recovery were all more than 75.0%,and the relative standard deviations were 3.52%-9.74% after spiked pesticides into wheat grain.The detection limit was 0.001 2 mg/kg,0.001 9 mg/kg,0.002 6 mg/kg,0.003 1 mg/kg and 0.004 d mg/kg respectively. At the same time, the inter-standard quantitative method based on omethoate was established and its linear regression equation and the correlation coefficient was y=17.743 6x＋1.274 9 and R2=0.989 8,respectively. Using this method, 3 samples were analyzed. As a result, this method was simple, accurate and precise for these 5 organophosphorus pesticides detection.