Characterization of Unknown Iodinated Disinfection Byproducts During Chlorination/Chloramination Using Ultrahigh Resolution Mass Spectrometry

Xin Wang^a,Juan Wang^a,Yahe Zhang^b,Quan Shi^b, Haifeng Zhang^a,Yu Zhang^a, Min Yang^a,⁎ 

^a State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China 

^b State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China

^*Corresponding author at: E-mail address: yangmin@rcees.ac.cn (M. Yang).

DOI: 10.1016/j.scitotenv.2016.02.157 

Keywords: Iodinated disinfection byproducts; Chlorination; Chloramination; Natural organic matter; Drinking water

Abstract: Iodinated disinfection byproducts (I-DBPs), formed from the reaction of disinfectant(s) with organic matter in the presence of iodide in raw water, have recently been focused because of their more cytotoxic and genotoxic properties than their chlorinated or brominated analogues. To date, only a few I-DBPs in drinking water have been identified. In this study, C18 solid phase extraction coupled with electrospray ionization ultrahigh resolu tion Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) was used to characterize un known I-DBPs in chloraminated/chlorinated water spiked with iodide and humic substances. In total, 178 formulas for one-iodine-containing products, 13 formulas for two-iodine-containing products, and 15 formulas for one-chlorine and one-iodine-containing products were detected in the chloraminated water sample, while only 9 formulas for one-iodine-containing products and 6 formulas for one-chlorine and one-iodine-containing products were found in the chlorinated water sample. Most I-DBPs have corresponding chlorine-containing an alogues with identical CHO compositions. As indicated by the modified aromaticity index(AImod), in the C18 ex tracts, more than 68% of the I-DBPs have aromatic structures or polycyclic aromatic structures. This result demonstrates that the use of chloramination as an alternative disinfection method may lead to the formation of abundant species of I-DBPs in the presence of iodide. Thus, the suitability of adopting chloramination as an al ternative disinfection method should be reevaluated, particularly when iodide is present in raw water.