Molecular Fingerprinting of Chlorinated Organic Compounds in Commercial Bottled Natural Sparkling Groundwater

Dissolved organic matter (DOM) is ubiquitous in natural sparkling groundwater (NSG), yet its molecular composition remains unexplored. Herein, 23 commercial NSG samples across China were sampled to investigate the molecular fingerprints of DOM, including chlorinated organic matter (Cl-OM), using optical techniques and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). For the HCO3––Na+-dominant hydrochemical type NSG water, nearly all water variables, including total organic chlorine concentrations, are within regulatory threshold values, and its DOM is dominated by autochthonous, lignin-like, and CHO molecules. However, Cl-OM molecules of all NSG samples account for 3.2 ± 3.0% of assigned molecule numbers, with CHOCl numbers overwhelmingly larger than CHONCl numbers. Moreover, the number of CHONCl molecules in NSG from Northeastern China is significantly lower than in other sources. These findings highlight the need to identify trace-level Cl-OM molecules by FT-ICR MS and to integrate DOM molecular information into NSG water quality evaluation and management.