Formation, Identification, and Occurrence of New Bromo- and Mixed Halo-Tyrosyl Dipeptides in Chloraminated Water

• Published in: Environmental science & technology 2019-04, Vol.53 (7), p.3672-3680
• Main Authors: Huang, Guang, Jmaiff Blackstock, Lindsay K, Jiang, Ping, Liu, Zhongshan, Lu, Xiufen, Li, Xing-Fang
• Format: Article
• Language: English
• Subjects: Byproducts; Chlorides; Disinfectants; Disinfection; Drinking water; High performance liquid chromatography; Iodides; Ions; Liquid chromatography; Mass spectrometry; Mass spectroscopy; Peptides; Quadrupoles; Raw water; Scientific imaging; Solid phases; Spectroscopy; Surface water; Treated water; Water analysis; Water sampling; Water treatment
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/acs.est.8b06831

Dipeptides are widely present in surface water and serve as precursors to form disinfection byproducts (DBPs) during disinfection (e.g., chloramination). Bromide (Br–) and iodide (I–) are common in many source waters, enhancing Br- and I-DBP formation. Recently Cl-, I-, and Cl-I-dipeptides were identified after chloramination of tyrosyl dipeptides in the presence of I– and were detected in authentic disinfected drinking water samples. However, the formation and occurrence of Br- and mixed halogen (Cl, Br, and/or I)-dipeptides in disinfected water have not been studied. Here we investigated the formation of halogenated dipeptides from three aromatic dipeptides, phenylalanylglycine (Phe-Gly), tyrosylalanine (Tyr-Ala), and tyrosylglycine (Tyr-Gly), under chloramination in the presence of Br– and I– at environmentally relevant levels ([Br–] and [I–], 0 and 0 μg L–1, 6 and 30 μg L–1, 30 and 30 μg L–1, 150 and 30 μg L–1, 300 and 30 μg L–1, and 900 and 30 μg L–1, respectively). For the first time, N-Br- and N,N-di-Br- as well as N-Br-N-Cl- and N-Br-3-I-tyrosyl dipeptides were identified using infusion electrospray quadrupole time-of-flight mass spectrometry. Tyrosyl dipeptides produced N-Cl-, 3-I-/3,5-di-I-, and N-Cl-3-I-tyrosyl dipeptides, while Phe-Gly formed only N-Cl-/N,N-di-Cl-Phe-Gly. To determine halogenated dipeptides in authentic water samples, we developed a new method of solid phase extraction and high-performance liquid chromatography with quadrupole ion trap mass spectrometry using reaction monitoring. 3,5-Di-I-Tyr-Ala and N-Br-Tyr-Ala were detected in treated water but not in the corresponding raw water, warranting further investigation into the occurrence of halogenated peptides in other drinking water systems.