Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China.
Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China.
Chemosphere. 2019 Jun;224:351-359. doi: 10.1016/j.chemosphere.2019.02.133. Epub 2019 Feb 22.
Haloacetic acids (HAAs) are the major disinfection byproducts (DBPs) that are formed during chlorination of drinking water. In this paper, the conversion of HAAs to amino acids (e.g., glycine) via ammonolysis was studied. First, a new and sensitive method for detecting glycine was developed by setting selected ion recording m/z 76 in positive electrospray ionization mass spectrometry coupled with ultra performance liquid chromatography. Second, among the mono-HAAs under the same test conditions, iodoacetic acid (49.3%) showed a considerably higher conversion to glycine during ammonolysis than chloroacetic acid (4.2%) and bromoacetic acid (27.7%). The conversion of iodoacetic acid to glycine increased with increasing temperature, increasing reaction time, or decreasing the ratio of (NH)CO to NH·HO in the aminating agent. Hydrolysis of iodoacetic acid to glycolic acid was also observed during ammonolysis, and it accounted for at most 50% of the iodoacetic acid conversion. The conversion to amino acids and the hydrolysis were the two major pathways during ammonolysis of HAAs. Third, compared with the iodoacetic acid sample and the simulated tap water sample without ammonolysis, the developmental toxicity of the corresponding samples with ammonolysis decreased by up to 10.4% and 32.1%, respectively. The ammonolysis was thus demonstrated to be a detoxification process for both individual HAAs and DBP mixture in chlorinated tap water. In practice, the ammonolysis of haloacid DBPs in tap water may be realized by simply adding an appropriate amount of an aminating agent during cooking.
卤乙酸（HAAs）是饮用水氯化消毒过程中形成的主要消毒副产物（DBPs）。本文研究了通过氨解将 HAAs 转化为氨基酸（例如甘氨酸）的反应。首先，通过在正电喷雾电离质谱联用超高效液相色谱中设置选择离子记录 m/z 76，开发了一种用于检测甘氨酸的新的、灵敏的方法。其次，在相同测试条件下的单卤乙酸中，碘乙酸（49.3%）在氨解过程中转化为甘氨酸的转化率明显高于氯乙酸（4.2%）和溴乙酸（27.7%）。碘乙酸转化为甘氨酸的转化率随着温度升高、反应时间延长或氨解剂中（NH）CO 与 NH·HO 比值降低而增加。在氨解过程中还观察到碘乙酸水解生成羟基乙酸，其最高占碘乙酸转化率的 50%。氨解过程中，HAAs 的转化为氨基酸和水解是两个主要途径。第三，与未经氨解的碘乙酸样品和模拟自来水样品相比，氨解后相应样品的发育毒性分别降低了 10.4%和 32.1%。因此，氨解是氯化自来水中单个 HAAs 和 DBP 混合物的解毒过程。在实际中，通过在烹饪过程中简单地添加适量的氨解剂，可能实现自来水中卤代酸 DBPs 的氨解。
