QuEChERS-GC/μECD法测定土壤中毒死蜱与氯氰菊酯残留

摘要

To determine residues of ch1orpyrifos and cypermethrin in soi1 simu1taneous1y and accurate1y, a rapid ana-1ytica1 method based on the modified QuEChERS ( Quick, Easy, Cheap, Effective, Rugged and Safe) for samp1e preparation and gas chromatography-microe1ectron capture detector ( GC/μECD) was estab1ished. The pesticides were extracted by aceto-nitri1e containing 0. 1% acetic acid with u1trasound assistance. The extracts were c1eaned-up by using PSA (primary seconda-ry amine) and C18 as adsorbents according to the method of QuEChERS, determined by GC/μECD, and quantified by exter-na1 standard method. The resu1ts showed that the ca1ibration curves were 1inear in the ranges of 0. 005-5. 000 mg/L for ch1or-pyrifos and 0. 01-5. 00 mg/L for cypermethrin, with corre1ation coefficients higher than 0. 999. The mean recoveries of two pesticides in soi1 ranged from 79. 52% to 96. 30% at spiked 1eve1s of 0. 01-0. 50 mg/kg with re1ative standard deviation (RSD, n=5) of 2. 03%-7. 67%. The 1imits of detection ( LOD, S/N﹥3 ) for ch1orpyrifos and cypermethrin were 0. 000 4 mg/kg and 0. 007 0 mg/kg and the 1imits of quan-tification (LOQ, S/N﹥10) were 0. 005 mg/kg and 0. 01 mg/kg, respective1y. Matrix effect on the quantitative resu1ts cou1d be neg1ected. The method is proved to be easy in operation, high in sensitivity, effective in purification, 1ow at cost and so1-vent saving, which is app1icab1e in ana1ysis and determination of ch1orpyrifos and cypermethrin in soi1.%为同时准确定量检测土壤中毒死蜱和氯氰菊酯残留量,建立了一种通过QuEChERS样品预处理方法和气相色谱/微池电子捕获检测器法( GC/μECD)快速测定土壤中这2种农药残留的方法.样品用含0.1%乙酸的乙腈超声提取,适量N-丙基乙二胺( Primary secondary amine, PSA)和C18填料净化,GC/μECD检测,外标法定量.结果表明,毒死蜱和氯氰菊酯的响应分别在0.005~5.000 mg/L、0.01~5.00 mg/L质量浓度范围内线性良好,相关系数r均大于0.999,在0.01~0.50 mg/kg 添加水平范围内,平均回收率在79.52%至96.30%之间,相对标准偏差(RSD, n=5)为2.03%~7.67%,检出限(信噪比大于3)分别为0.0004 mg/kg、0.0070 mg/kg,定量限(信噪比大于10)分别为0.005 mg/kg、0.010 mg/kg.基质效应对定量结果的影响可忽略不计.该方法操作简便、灵敏度高、干扰少,分析成本低,节省溶剂,适合于毒死蜱与氯氰菊酯在土壤中的残留分析与检测.