固相萃取-气相色谱-质谱法测定饮用水中15种农药残留量

SPE-GC-MS Determination of Residual Amounts of 15 Pesticides in Drinking Water

取水样1.00L,在经活化的C18固相萃取小柱上富集(流量10mL·min^(-1)),用乙酸乙酯15.0 mL洗脱。洗脱液用无水硫酸钠脱水,氮吹浓缩并干燥,加乙酸乙酯溶解残渣并定容至1.0mL,过滤。滤液经气相色谱分离后采用电子轰击离子源和选择离子监测模式进行质谱分析。15种农药的质量浓度在1.00~50.0μg·L^(-1)内与峰面积呈线性关系,检出限(3S/N)在0.05~0.21μg·L^(-1)之间。按标准加入法进行回收试验,测得回收率在90.4%~98.8%之间,测定值的相对标准偏差(n=6)在1.1%~2.7%之间。

Pesticides in the water sample （1. 00 L） were enriched with a flow rate of 10 mL · min^-1 on activated C18 solid phase extraction column and the analytes were eluted from the column with 15. 0 mL of ethyl acetate. The eluate was dehydrated with anhydrous sodium sulfate, concentrated and dried by nitrogen blowing. The residue was taken up with ethyl acetate and made up its volume to 1.0 mL, and the solution was filtered. After separation by CK;, MS analysis was carried out under the condition of EI and SIM. Linear relationships between values of peak area and mass concentration of the 15 pesticides were found in the same range of 1.00--50. 0 μg · L^-1 , with detection limits （3S/N） in the range of 0. 05--0. 21 μg · L^-1. Test for recovery was made by standard addition method, giving results in the range of 90. 4%-98. 8%, with RSDs （n=6） ranged from 1.1% to 2. 7%.