提出了液相色谱-串联质谱法测定生活饮用水中二氯乙酸、三氯乙酸、一碘乙酸和二碘乙酸等4种卤代乙酸含量的方法。取0.5 mL过滤后的水样,与0.5 mL乙腈混合。以Torus DEA色谱柱为固定相,以体积比10∶90的含1.0 mmol·L^-1乙酸铵的2.0%(体积分数)氨水溶液-乙腈混合液为流动相进行等度洗脱。分离后的4种目标物经电喷雾离子源负离子模式扫描,采用多反应监测模式进行检测,外标法定量。结果显示:4种卤代乙酸的质量浓度在5~100 μg·L^-1内与定量离子峰面积呈线性关系,检出限(3S/N)为0.3~3.0 μg·L^-1;对自来水水样进行3个浓度水平的加标回收试验,回收率为70.1%~114%,测定值的相对标准偏差为(n=6)为0.90%~5.8%;方法用于10份末梢水分析,其中一碘乙酸、二碘乙酸和三氯乙酸均未检出,有8份样品检出二氯乙酸,检出量为2.0~4.4 μg·L^-1。

A method for the determination of four haloacetic acids including dichloroacetic acid, trichloroacetic acid, monoiodoacetic acid and diiodoacetic acid in drinking water by liquid chromatography-tandem mass spectrometry was proposed. The filtered water sample (0.5 mL) was taken and mixed with 0.5 mL of acetonitrile. Torus DEA column was used as stationary phase, and isocratic elution was performed by the mixed solution composed of 2.0% (volume fraction) ammonia solution containing 1.0 mmol·L^-1 ammonium acetate and acetonitrile at volume ratio of 10∶90 as mobile phase. Four separated targets were scanned by electrospray ion source with negative ion mode, detected by multi-reaction monitoring mode, and quantified by external standard method. As shown by the results, linear relationships between the mass concentrations of four haloacetic acids and the peak areas of quantitative ions were kept in the range of 5-100 μg·L^-1, with detection limits (3S/N) in the range of 0.3-3.0 μg·L^-1. Test for recovery was made on the tap water sample at 3 concentration levels by standard addition method, giving results in the range of 70.1%-114%, and RSDs (n=6) of the determined values ranged from 0.90% to 5.8%. The method was used to analyze 10 samples of peripheral water, in which monoiodoacetic acid, diiodoacetic acid and trichloroacetic acid were not detected, with the detected amount of dichloroacetic acid in the range of 2.0-4.4 μg·L^-1 in 8 samples.