气相色谱-质谱法测定水-沉积物系统中39种农药残留

建立了气相色谱-质谱(GC-MS)同时测定水体和沉积物中39种农药残留的检测方法。水体样品由乙酸乙酯萃取，无水硫酸钠干燥；沉积物样品经乙腈超声提取，采用N-丙基乙二胺(PSA)和石墨化碳黑(GCB)净化，选择离子监测模式(SIM)进行检测，外标法定量。结果表明:39种农药在10~1 000 μg/L范围内线性关系良好，决定系数(R2)均大于0.9950。空白水样在0.25、0.5、5.0 μg/L 3个添加水平下的平均回收率在72%~111%之间，相对标准偏差(RSD，n = 5) 在1.1%~10%之间，检出限(LOD)为0.02~0.06 μg/L，定量限(LOQ)为0.04~0.18 μg/L；空白沉积物在5.0、20.0、100.0 μg/kg 3个添加水平下的回收率在65%~119%之间，RSD (n = 5)在2.1%~12%之间，LOD为0.7~1.5 μg/kg，LOQ为2.1~4.3 μg/kg。该方法灵敏、准确，结果可靠，可满足水体和沉积物中39种目标农药的残留分析要求。

Determination of 39 pesticides in water and sediments by gas chromatography-mass spectrometry

A gas chromatography-mass spectrometry (GC-MS) method for the simultaneous determination of 39 pesticides residues in water and sediments was developed. The water sample was extracted with ethyl acetate and was passed through a column loaded with anhydrous sodium sulfate. The sediment sample was ultrasonically extracted with acetonitrile and then cleaned up with N-propyl ethylenediamine (PSA) and graphitized carbon black (GCB). The pesticide residues were detected in selected ion monitoring (SIM) mode and was quantified by external standard method. The results showed that the linear relationship of the 39 pesticides was good with coefficient of determination (R2) > 0.9950. The recoveries of pesticides spiked in blank water samples at three levels (0.25, 0.5, and 5.0 μg/L) were in range of 72%-111%, with the relative standard deviation (RSD, n = 5) of 1.1%-10%. The limits of detection (LODs) were 0.02-0.06 μg/L and the limits of quantification (LOQs) were 0.04-0.18 μg/L. The average recoveries of pesticides spiked in blank sediment samples at three levels (5.0, 20.0, and 100.0 μg/kg) were in range of 65%-119%, with the RSD of 2.1%-12%. The LODs were 0.7-1.5 μg/kg and the LOQs were 2.1-4.3 μg/kg. The established method is sensitive, accurate, and reliable. It is suitable for the detection of 39 target pesticides in water and sediments.