生活饮用水中14种农药残留的全自动固相萃取-气相色谱质谱联用测定法

目的探索并建立生活饮用水中14种农药残留的固相萃取-气相色谱质谱联用(GC-MS)检测方法。方法通过全自动固相萃取提取水中农药残留,对固相萃取柱、水样pH值、洗脱溶剂种类与体积等进行优化。对比气相色谱-质谱-选择离子扫描模式(GC-MS-SIM)和气相色谱-质谱-多离子扫描模式(GC-MS-MRM)的检出限和灵敏度。结果采用C18固相萃取柱、水样pH调节在1～2之间进行萃取,用10 mL乙酸乙酯-二氯甲烷(V/V=1∶1)以0.5 m L/min的速度进行洗脱,所得的效果较佳。GC-MS-MRM检出限更低灵敏度更高。通过3个浓度水平的加标回收实验,在GC-MS-MRM扫描模式下,方法的回收率为70.9%～116.3%,相对标准偏差(RSD)为2.16%～6.39%,方法的检出限范围为0.000 1～0.050 0μg/L,定量限为0.000 3～0.150 0μg/L。结论本方法在样品前处理中有机溶剂使用量少,便于自动操作,检测结果准确,灵敏度高,能够应用于饮用水中多种农药检测。在优化条件下,GC-MS-MRM检测方法能有效满足水中痕量有机氯检测的要求。

Determination of 14 pesticide residues in drinking water by automatic solid phase extraction and gas chromatography-mass spectrometry

Objective To explore and establish a method for the determination of 14 pesticide residues in drinking water by automatic solid phase extraction and gas chromatography-mass spectrometry(GC-MS).Methods The pesticide residues in water were extracted by automatic solid phase extraction.The solid phase extraction column,pH of water sample,elution solvent type and volume,and elution velocity were optimized.The detection limit and sensitivity between gas chromatography-mass spectrometry-selective ion scanning mode(GC-MS-SIM)and the gas chromatography-mass spectrometry-multi-ion scanning mode(GC-MS-MRM)were compared.Results The C18 solid phase extraction column and water sample pH of 1-2,elute with 10 mL of ethyl acetate dichlorometha ne(V/V=1∶1)at a rate of 0.5 mL/min reached the best effect.GC-MS-SIM had lower detection limit and higher sensitivity.By the recovery experiments by 3 concentration levels,in GC-MS-MRM,the recovery rate ranged from70.9%to 116.3%,the relative standard deviation(RSD)ranged from 2.19%to 6.39%,the detection limit ranged from0.0001 to 0.0500μg/L,and the limit of quantification ranged from 0.0003 to 0.1500μg/L.Conclusion The method has less use of organic solvents in sample pretreatment,and is convenient for automatic operation,accurate detection and high sensitivity.It can be applied to the detection of various pesticides in drinking water.Under the optimized conditions,GC-MS-MRM can effectively meet the requirements of the detection of trace organic chlorine in water.