扩大分散液液微萃取法测定水中20种有机氯和菊酯农药残留

Determination of 20 organochlorine and pyrethroid pesticides residues in water by dispersive liquid-liquid microextraction

本研究建立了扩大液液分散微萃取测定饮用水中20种有机氯和菊酯农药残留的方法。通过扩大分散液液萃取(dispersive liquid-liquid microextraction,DLLME)提取水中农药残留,对DLLME萃取相关的影响因素进行了优化:40 mL水样用0.4 mL三氯甲烷与4 mL乙腈作为萃取剂和分散剂,萃取离心后取出用氮吹吹干,100μL正己烷溶剂置换后进气相色谱电子捕获检测器(GC-ECD)检测。结果显示,水中20种有机氯及拟除虫菊酯农药的线性分别在0.002~0.10μg·mL-1和0.01~0.20μg·mL-1的浓度范围内良好,相关系数r>0.998,方法检出限为0.001~0.002μg·L-1,方法富集倍数为168~206,高、中、低3水平浓度加标回收率在83.30%~116.70%,相对标准偏差(RSD)为0.84%~9.87%。采用所建立的方法对135个农村饮用水样品进行检测,结果均远低于限量值。该方法灵敏度、准确性高,稳定性好,批量分析时更具有可操作性,适用于饮用水中有机氯及拟除虫菊酯的定性定量分析。

In this study,a method for the determination of 20 organochlorine and pyrethroid pesticide residues in drinking water was established by dispersive liquid-liquid microextraction(DLLME).The influencing factors related to DLLME extraction were optimized by expanding the extraction of pesticide residues in water by expanding dispersive liquid-liquid microextraction:0.4 mL of chloroform and 4 mL of acetonitrile were used as extractants and dispersants for 40 mL of water samples,extracted and centrifuged and dried with nitrogen,and 100μL of n-hexane solvent was replaced by gas chromatography electron capture detector(GC-ECD)for detection.The results showed that the linearity of 20 organochlorine and pyrethroid pesticides in water was good in the concentration range of 0.002-0.10μg·mL-1 and 0.01-0.20μg·mL-1,respectively,the correlation coefficient was 0.998,and the detection limit of the method was 0.001-0.002μg·L-1,the enrichment folds of the method were 168-206,the recoveries of the high,medium and low concentrations were 83.30%-116.70%,and the relative standard deviation(RSD)was 0.84%-9.87%.The established method was used to test 135 rural drinking water samples,and the results were below the limit values.This method has high sensitivity,accuracy,good stability,and is more operable in batch analysis,and is suitable for the qualitative and quantitative analysis of organochlorine and pyrethroid in drinking water.