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目的建立水中18种农药的固相萃取-气相色谱-质谱分析方法。方法利用C_(18)固相萃取小柱预处理水样,通过对固相萃取条件的优化,得出了最佳实验条件:水样加0.5 g氯化钠和2 ml甲醇作为改进剂,上样流速为10 ml/min,洗脱溶剂为乙酸乙酯和正己烷,洗脱体积为10 ml,洗脱速率为2 ml/min;GC-MS采用HP-5MS石英毛细管色谱柱(30 m×0.25 mm,0.25μm)分离18种农药,氦气为载气,柱流量为1.0 ml/min,进样体积为1.0μl。选择电子轰击离子源(EI),辅助线温度为280℃,离子源温度为230℃,四极杆温度为150℃;加入菲-d10作为内标,利用选择离子监测(SIM)模式进行定性定量。结果 18种农药的方法检出限为0.000 07 mg/L~0.000 31 mg/L,加标回收率为72.5%~105.1%,相对标准偏差(RSD)为1.1%~9.7%。结论本法同时测定水中18种农药,操作简便、省时、灵敏,环境污染小。
Objective To establish a method for the determination of 18 pesticides in water by gas chromatography-mass spectrometry. Methods The water samples were pretreated with C_ (18) solid phase extraction cartridges, and the optimum conditions were obtained by optimizing the solid phase extraction conditions: water sample plus 0.5 g sodium chloride and 2 ml methanol as the improver The flow rate was 10 ml / min, the elution solvent was ethyl acetate and n-hexane, the elution volume was 10 ml and the elution rate was 2 ml / min. The GC-MS was characterized by HP-5MS quartz capillary column 0.25 mm, 0.25 μm) to separate 18 pesticides with helium as the carrier gas at a column flow of 1.0 ml / min and a sample volume of 1.0 μl. Electron bombardment ion source (EI) was selected with an auxiliary line temperature of 280 ° C, an ion source temperature of 230 ° C and a quadrupole temperature of 150 ° C; phenanthrene-d10 was added as an internal standard and quantitatively quantified using SIM mode . Results The detection limits of 18 pesticides ranged from 0.000 07 mg / L to 0.000 31 mg / L, and the recoveries were 72.5% -105.1%. The relative standard deviations (RSDs) ranged from 1.1% to 9.7%. Conclusion This method is applicable to the simultaneous determination of 18 kinds of pesticides in water. The method is simple, time-saving, sensitive and environment-friendly.