Zhao Jiaxing, Hu Shaoyang, Zhu Lizhong, Wang Wei
Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China.
Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China.
Sci Total Environ. 2022 Jun 15;825:153904. doi: 10.1016/j.scitotenv.2022.153904. Epub 2022 Feb 19.
Chlorinated halobenzoquinones (HBQs) widely exist in drinking water as emerging disinfection byproducts (DBPs), which have attracted significant attention due to their wide occurrence and high toxicity. In this study, the formation of chlorinated HBQs from the three free aromatic amino acids, tryptophan (Trp), tyrosine (Tyr) and phenylalanine (Phe), during chlorination was investigated, the formation pathways of chlorinated HBQs were explained based on the detected intermediates and influence factors. The results revealed that four chlorinated HBQs, including 2,6-dichloro-1,4-benzoquinone (2,6-DCBQ), 2,3,5-trichloro-1,4-benzoquinone, 2,3,5,6-tetrachloro-1,4-benzoquinone and 2,6-dichloro-3-methyl-1,4-benzonquinone, were formed in chlorination of the three free aromatic amino acids, and 2,6-DCBQ was the dominant species among the formed chlorinated HBQs. Of the three free aromatic amino acids, Trp and Tyr presented relatively high yields of chlorinated HBQs than Phe. Moreover, ten intermediates were successfully detected (e.g., N,2-dichloroaniline from Trp, 2,4,6-trichlorophenol from Tyr) according to the isotope and fragment information obtained using high resolution mass spectrometry. The formation pathways of chlorinated HBQs from Trp and Tyr were proposed to include electrophilic addition, electrophilic substitution, oxidation, deacidification and dehydration reaction, and further validated using theoretical calculation. The yields of chlorinated HBQs during chlorination of the free aromatic amino acids were significantly affected by free chlorine dosage, pH and temperature.
氯化卤代苯醌（HBQs）作为新出现的消毒副产物（DBPs）广泛存在于饮用水中，由于其广泛存在和高毒性而备受关注。本研究考察了三种游离芳香族氨基酸，即色氨酸（Trp）、酪氨酸（Tyr）和苯丙氨酸（Phe）在氯化过程中氯化HBQs的形成情况，根据检测到的中间体和影响因素解释了氯化HBQs的形成途径。结果表明，在三种游离芳香族氨基酸的氯化过程中形成了四种氯化HBQs，包括2,6 - 二氯 - 1,4 - 苯醌（2,6 - DCBQ）、2,3,5 - 三氯 - 1,4 - 苯醌、2,3,5,6 - 四氯 - 1,4 - 苯醌和2,6 - 二氯 - 3 - 甲基 - 1,4 - 苯醌，且2,6 - DCBQ是所形成的氯化HBQs中的主要物种。在这三种游离芳香族氨基酸中，Trp和Tyr的氯化HBQs产率相对高于Phe。此外，根据使用高分辨率质谱获得的同位素和碎片信息，成功检测到了十种中间体（例如，来自Trp的N,2 - 二氯苯胺、来自Tyr的2,4,6 - 三氯苯酚）。提出了Trp和Tyr形成氯化HBQs的途径包括亲电加成、亲电取代、氧化、脱酸和脱水反应，并通过理论计算进一步验证。游离芳香族氨基酸氯化过程中氯化HBQs的产率受到游离氯剂量、pH值和温度的显著影响。
