Nontarget Analysis Of Halogenated Disinfection Byproducts In Tap Water Using Ultra-high Performance Liquid Chromatography-high Resolution Mass Spectrometry

In chlorination disinfection process of water,chlorinated disinfectants can react with organic components to give rise to a variety of halogenated disinfection byproducts（HDBPs）.Most of HDBPs possess toxicity,potentially affecting human health.To date,in addition to regulated HDBPs,numerous HDBPs in tap water have not been identified.In this study,a nontarget analysis method based on ultra-high performance liquid chromatography-high resolution mass spectrometry（UPLC-HRMS）was developed for screening and identification of HDBPs in tap water,source water,tea and coffee.The main research contents and results are as the following:1.A nontarget analysis method based on UPLC-HRMS was developed for screening and identification of HDBPs（including chlorinated,brominated,iodinated and mix-chlorinated/brominated/iodinated DBPs）.HDBPs were structurally elucidated via retention times,MS/MS（Date Dependent Acquisition）spectra and fragmental pathways.Toxicological properties of the identified HDBPs were calculated and predicted.Ten HDBPs（including pentachlorophenol,3-chlorophenol,4-chloro-3-methylphenol,trichlorophenol,4-chloro-3,5-dimethylphenol,dichlorophen,hexachlorophene,tetrachlorobisphenol A,tetrabromobisphenol A and 4-bromo-2-iodophenol）were quantitatively analyzed using internal standard method.Identified HDBPs were semi-quantitatively analyzed by peak area.2.The nontarget analysis method was used for screening of HDBPs in tap water from residential homes in six regions of Guangzhou and Shenzhen City.In total,446 HDBPs formulae were finally identified,including 339 chlorinated DBPs,79 brominated DBPs and28 mix-chlorinated/brominated DBPs.The results indicated that the number of HDBPs in Guangzhou tap water was generally larger than that in Shenzhen tap water.Seven HDBPs（including CHCl₃,CH₂O₃SCl₂,CHO₃SCl₃,C₂HO₂Cl₃,C₆H₄OCl₂,C₆H₄O₃SCl₂ and C₆HO₃SCl₅）were structurally elucidated.The toxicity prediction results indicated that which are all in possession of developmental toxicity and acute toxicity.The concentrations of ten HDBPs in the tap water of six regions were ND-13.91 ng/L.Seven identified HDBPs were semi-quantitatively analyzed,of which the concentrations in the tap water of six regions were ND-4.55 ng/L.3.The nontarget analysis method was used for screening of HDBPs in source water collected form Dongjiang River and the tap water from Huizhou city.In total,594 HDBPs formulae were finally identified,including 443 Cl-DBPs,108 Br-DBPs,40 Cl Br-DBPs and 3I-DBPs.The results indicated that the source water could form a lot of HDBPs after chlorination.Source water collected form middle reaches could form more HDBPs due to human activities.Seven halogenated phenols（including C₆H₅OBr、C₆H₅OI、C₇H₄O₃Cl I、C₆H₄O₄SCl₂、C₆H₃O₄SCl₃、C₆H₃OCl₂Br and C₆H₃OCl Br₂）were structurally elucidated.The toxicity prediction results indicated that all of them possessed acute toxicity,and C₆H₅OBr、C₆H₅OI and C₆H₃O₄SCl₃ possessed developmental toxicity.The quantification results of ten HDBPs are as the following:the concentrations of ten HDBPs in source water without chlorination were ND-4.05 ng/L,in source water with chlorination were ND-6.99 ng/L,and in tap water were ND-3.83 ng/L.The semi-quantitative concentrations of seven identified halogenated phenols in source water,source water with chlorination and tap water were ND-141.63 pg/L.4.The nontarget analysis method was used for the screening of HDBPs in tea and coffee.In total,82 Cl-DBPs formulae were finally identified,including 59 Cl₁-DBPs,15Cl₂-DBPs and 8 Cl₃-DBPs.Eight catechin-containing Cl-DBPs were identified via retention times,MS/MS（DDA）spectra and fragmental pathways,and catechin,gallocatechin,catechin gallate and gallocatechin gallate were determined to be their precursors.Eight catechin-containing Cl-DBPs could be structurally elucidated.The toxicity prediction results indicated that eight catechin-containing Cl-DBPs possessed developmental toxicity,mutagenicity and acute toxicity.The semi-quantified concentrations of eight catechin-containing Cl-DBPs in tea and coffee brewed by tap water were ND-25.39μg/L.In this study,a lot of HDBPs were identified in tap water,source water,tea and coffee by the nontarget analysis method,and 22 HDBPs could be structurally elucidated.These HDBPs generally possessed developmental toxicity and acute toxicity and were widely distributed in water as potential contaminants affecting human health.