摘要
建立在线衍生-顶空气相色谱法测定饮用水中的二氯乙酸和三氯乙酸。以对甲基苯磺酸为催化剂、甲基叔丁醚为萃取剂,将饮用水中的二氯乙酸、三氯乙酸于顶空瓶内与甲醇在线衍生酯化,采用顶空气相色谱法测定所得酯化产物,用标准曲线法定量。利用正交试验对顶空进样器条件、催化剂及萃取剂等参数进行优化。进样分流比为10∶1,柱温箱初始温度为40.0℃,梯度升温至200.0℃,保留1.0 min;载气(氮气)流量为1.5 mL/min;检测器温度为250.0℃。二氯乙酸和三氯乙酸的质量浓度在5.0~200.0μg/L范围内与色谱峰面积线性关系良好,相关系数均大于0.999,方法检出限分别为0.1、0.2μg/L,定量限分别为0.3、0.7μg/L。样品加标平均回收率分别为96.8%~98.2%、95.8%~101%,测定结果的相对标准偏差分别为1.3%~2.5%、3.7%~4.4%(n=6)。该方法为饮用水中二氯乙酸和三氯乙酸的常规测定提供了一种快速、灵敏、可靠的方法。
An online derivatization headspace gas chromatography method was established for the determination of dichloroacetic acid(DCA)and trichloroacetic acid(TCA)in drinking water.Using p-toluenesulfonic acid as the catalyst and methyl tert-butyl ether as the extraction solvent,DCA and TCA in drinking water were esterified online with methanol in the headspace vial.The resulting methyl esters were determined by headspace-gas chromatography equipped with an electron capture detector(ECD)and quantified by standard curve method.The experimental parameters of the headspace sampler,catalyst and extraction solvent were optimized through orthogonal experiments.The injection was performed with a split ratio of 10:1.The oven temperature was initially set at 40.0℃,ramped to 200.0℃,and held for 1.0 min.Nitrogen was employed as the carrier gas at a flow rate of 1.5 mL/min,and the detector temperature was maintained at 250.0℃.The mass concentration of DCA and TCA had good linear relationship with the chromatographic peak area in the range of 5.0-200.0μg/L,and the correlation coefficients were all more than 0.999.The detection limits of the method were 0.1μg/L and 0.2μg/L,and the quantification limits were 0.3μg/L and 0.7μg/L,respectively.The average recoveries of spiked samples were 96.8%-98.2%and 95.8%-101%,and the relative standard deviations of the determination results for six parallel samples were 1.3%-2.5%and 3.7%-4.4%,respectively.The proposed method provides a rapid,sensitive,and reliable approach for the routine determination of dichloroacetic acid and trichloroacetic acid in drinking water.
作者
尚士博
刘盛田
SHANG Shibo;LIU Shengtian(Department of Physical and Chemical Laboratory,Shunyi Center for Disease Control and Prevention,Beijing 101300,China)
出处
《化学分析计量》
2026年第1期125-131,共7页
Chemical Analysis And Meterage
关键词
酯化反应
饮用水
二氯乙酸
三氯乙酸
顶空气相色谱法
esterification reaction
drinking water
dichloroacetic acid
trichloroacetic acid
headspace gas chromatography
