Discovery of Emerging Disinfection by-products in Water using Gas Chromatography coupled with Orbitrap-based Mass Spectrometry

Abstract

The disinfection of drinking water is required in order to protect consumers from potential waterborne infectious and parasitic pathogens. Water is commonly treated by adding chemical disinfectants, such as free chlorine, chloramines, chlorine dioxide, and ozone. However, although very effective in removing disease-causing microorganisms, these disinfectants can react with naturally occurring materials in the water and can form disinfection by-products (DBPs) which can be harmful to human health. In particular, compounds containing an iodo-group, i.e., iodinated DBPs (iodo-DBPs), may pose a greater health risk for the population exposed to them than their brominated and chlorinated analogues [1]. In recent years, several chemical classes of low molecular weight iodo-DBPs have been reported; however, many more may be still present in the unknown fraction (~50%) of halogenated material formed during disinfection treatments [2]. Therefore, complete characterization of iodo-DBPs present in DBP mixtures is crucial to further investigate their occurrence in disinfected waters and potential toxicity effects. The identification of emerging iodinated DBPs in water is difficult due to the complexity of this matrix and the low concentrations of these compounds. For this, analytical techniques with high resolving power, high mass accuracy and sensitivity are required. In this work, a novel gas chromatography (GC), coupled with high-resolution accurate mass Orbitrap mass spectrometer (the Thermo Scientific™ Q Exactive™ GC hybrid quadrupole-Orbitrap mass spectrometer), has been used for iodo-DBPs detection and accurate mass identification in chlorinated and chloraminated water samples