title: Nontargeted identification of peptides and disinfection byproducts in water.
abstract: A broad range of organic compounds are known to exist in drinking water sources and serve as precursors of disinfection byproducts (DBPs). Epidemiological findings of an association of increased risk of bladder cancer with the consumption of chlorinated water has resulted in health concerns about DBPs. Peptides are thought to be an important category of DBP precursors in water. However, little is known about the actual presence of peptides and their DBPs in drinking water because of their high sample complexity and low concentrations. To address this challenge and identify peptides and non-chlorinated/chlorinated peptide DBPs from large sets of organic compounds in water, we developed a novel high throughput analysis strategy, which integrated multiple solid phase extraction (SPE), high performance liquid chromatography (HPLC) separation, and non-target identification using precursor ion exclusion (PIE) high resolution mass spectrometry (MS). After MS analysis, structures of candidate compounds, particularly peptides, were obtained by searching against the Human Metabolome Database (HMDB). Using this strategy, we successfully detected 625 peptides (out of 17,205 putative compounds) and 617 peptides (out of 13,297) respectively in source and finished water samples. The source and finished water samples had 501 peptides and amino acids in common. The remaining 116 peptides and amino acids were unique to the finished water. From a subset of 30 putative compounds for which standards were available, 25 were confirmed using HPLC-MS analysis. By analyzing the peptides identified in source and finished water, we successfully confirmed three disinfection reaction pathways that convert peptides into toxic DBPs.
authors.affiliation: Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB T6G 2G3, Canada. Electronic address: yanan3@ualberta.ca.
authors.forename: Yanan
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Department of Computer Science, University of Alberta, Edmonton, AB T6G 2E8, Canada.
authors.forename: Ying
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB T6G 2G3, Canada.
authors.forename: Feng
authors.initials: F
authors.lastname: Li
authors.affiliation: Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB T6G 2G3, Canada.
authors.forename: Lindsay
authors.initials: L
authors.lastname: Jmaiff
authors.affiliation: Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB T6G 2G3, Canada.
authors.forename: Steve E
authors.initials: SE
authors.lastname: Hrudey
authors.affiliation: Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB T6G 2G3, Canada. Electronic address: xingfang.li@ualberta.ca.
authors.forename: Xing-Fang
authors.initials: XF
authors.lastname: Li
mesh_terms: D002853:Chromatography, Liquid; D004202:Disinfectants / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D010455:Peptides / Q000032:analysis*; D052616:Solid Phase Extraction; D021241:Spectrometry, Mass, Electrospray Ionization; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D004202:Disinfectants; D010455:Peptides; D014874:Water Pollutants, Chemical
keywords: Disinfection byproducts; Mass spectrometry; Nontargeted detection; Peptide; Water analysis