GC-MS测定生活饮用水及水源水中6种酰胺类除草剂

Determination of Six Amide Herbicides in Drinking Water and Source Water by GC-MS

目的建立生活饮用水及水源水中甲草胺、乙草胺、丙草胺、丁草胺、异丙草胺、异丙甲草胺的气相色谱—质谱联用(GC-MS)测定方法。方法水样中6种酰胺类除草剂通过C_(18)固相萃取柱吸附萃取,用乙酸乙酯洗脱,洗脱液经脱水、浓缩定容后,用GC-MS分析测定。根据待测物的保留时间和质谱图定性,再通过待测物的定量离子外标法定量。结果本法分离效果好,测定曲线浓度范围(5.0~250)μg/L,若取水样500 mL浓缩至1.0 mL测定,样品测定的最低检测质量浓度为0.01μg/L。当样品加标浓度为0.02、0.20和0.50μg/L时,方法的加标回收率范围为78.6%~106.4%,连续测定6次,相对标准偏差(RSD)为1.7%~6.8%。对待测组分在水中的稳定性进行研究表明,样品于4℃保存24 h后仍可获得较稳定的结果。结论该方法操作简便,灵敏度高,可用于生活饮用水及水源水中6种酰胺类除草剂的测定。

Objective To establish a method for the determination of alachlor,acetochlor,pretilachlor,butachlor,propisochlor and metolachlor in drinking water and source water by gas chromatography-mass spectrometry(GC-MS).Methods Six amide herbicides in water samples were extracted by a C_(18) solid-phase extraction column and eluted with ethyl acetate.The eluent was dehydrated,concentrated to a fixed volume,and then separated and determined by GC-MS.A qualitative analysis was performed based on the retention time and mass spectrum of the substance to be determined,and a quantitative analysis was performed by the quantitative ion external standard method.Results This method had a good separation effect,and the concentration range was 5.0-250μg/L on the determination curve,if 500 mL water sample was concentrated to 1.0 mL,the limit of detemination was 0.01μg/L.When the spiked concentrations of the samples were 0.02,0.20 and 0.50μg/L,respectively,the recoveries of the method ranged from 78.6%to 106.4%,and the relative standard deviations were between 1.7%and 6.8%for six consecutive measurements.The stability of the components to be determined in water was studied,and the results showed that accurate results were obtained after the samples were stored at 4℃for 24 hours.Conclusion The method is simple and highly sensitive and can be used for the determination of six amide herbicides in drinking water and source water.