低温富集液液萃取-气相色谱-串联质谱法测定水样中15种农药残留

GC-MS/MS Determination of Residual Amounts of 15Pesticides in Water Samples with Low-Temperature Enrichment Liquid-Liquid Extraction

利用低温冷冻条件下农药在水相和有机相之间达到新的传质平衡,建立了低温富集液液萃取-气相色谱-三重四极杆串联质谱法同时测定水样中15种有机磷、有机氯及菊酯类农药的方法。通过对样品前处理中的溶剂选择、冷冻温度及冷冻时间的优化,最终确定的样品前处理条件为:萃取溶剂为甲苯2.0 mL;冷冻温度-40℃;冷冻时间1h。15种农药的检出限(3S/N)在0.005~0.02μg·L-1范围,测定下限(10S/N)为0.02~0.07μg·L-1。方法用于水样中农药的分析,加标回收率在78.8%~124%之间,测定值的相对标准偏差(n=5)在0.9%~9.1%之间。

Based on the fact that pesticides reach a new mass transfer balance between the water and organic phases at freezing temperature,a novel sample enrichment method was established for simultaneous determination of15pesticides(organochlorine,organophosphorus and pyrethroid)in water combining gas chromatography-triple quadropole mass spectrometry with low temperature enrichment liquid-liquid extraction.The following conditions were optimized,the extraction solvents,freezing temperature and time:extraction solvent was toluene(2.0mL),the freezing temperature was-40 ℃,and the freezing time was 1h.The detection limits(3S/N)and lower limits of determination(10S/N)found were in the ranges of 0.005-0.02μg·L-1 and 0.02-0.07 μg·L-1,respectively.The proposed method was applied to the analysis of water sample,giving values of recovery and RSD′s(n=5)in the ranges of 78.8%-124% and 0.9%-9.1%,respectively.