提出了吹扫捕集-气相色谱法测定海水淡化过程产生的浓盐水中氯乙酸含量的方法。样品(25.00 mL)在60 ℃下经硫酸-甲醇(1+9)溶液衍生化60 min。取衍生化后的溶液20 mL,用吹扫捕集进样,并用HP-5石英毛细管色谱柱分离,电子捕获检测器检测。二氯乙酸和三氯乙酸的质量浓度在120.0 μg·L-1以内与其峰面积均呈线性关系,检出限(3S/N)分别为0.15,0.84 μg·L-1。以浓盐水样品为基体进行加标回收试验,所得回收率在87.2%~112%之间,测定值的相对标准偏差(n=6)在1.1%~2.7%之间。

A method of GC for the determination of chloroacetic acids in brine discharged from process of seawater desalination with sampling by purging and trapping was proposed. The sample (25.00 mL) was derivatized with a mixture of sulfuric acid and methanol (1+9) for 60 min at 60 ℃. The derivatized solution (20 mL) was introduced by purging and trapping, separated on HP-5 quartz capillary column and detected by μECD. Linear relationships between values of peak area and mass concentration of di and tri-chloroacetic acid were kept in the same range within 120.0 μg·L-1 with detection limits (3S/N) of 0.15 and 0.84 μg·L-1 respectively. On the base of a brine sample, test for recovery was made by standard addition method, values of average recovery found were in the range of 87.2%-112%, with RSD′s (n=6) in the range of 1.1%-2.7%.