1. Observation of inconsistent carbon isotope compositions of chlorine-isotopologue pairs of individual organochlorines by gas chromatography-high resolution mass spectrometry
- Author
-
Tang, Caiming, Tan, Jianhua, Fan, Yujuan, Zheng, Ke, Huang, Qiuxin, and Peng, Xianzhi
- Subjects
Chemical Physics (physics.chem-ph) ,Physics - Instrumentation and Detectors ,Physics - Chemical Physics ,FOS: Physical sciences ,Instrumentation and Detectors (physics.ins-det) - Abstract
This study investigated the consistency/inconsistency of carbon isotope compositions of chlorine-isotopologue pairs, e.g., 12C235Cl4 vs. 12C13C35Cl4, of individual organochlorines including two chloroethylenes, three polychlorinated biphenyls, methyl-triclosan and hexachlorobenzene. The raw carbon isotope ratios were measured by gas chromatography-high resolution mass spectrometry. Data simulations in terms of background subtraction, background addition, dual 13C-atoms substitution, deuterium substitution and hydrogen-transfer were conducted to confirm the validity of measured carbon isotope ratios and their differences. Inconsistent carbon isotope ratios derived from chlorine-isotopologue pairs of individual organochlorines were observed, and the isotopologues of each organochlorine were thus inferred to be non-randomly distributed. Mechanistic interpretation for these findings was tentatively proposed according to a basic principle in clumped-isotope geochemistry, reaction thermodynamics and kinetics, along with isotope effects occurring on electron ionization mass spectrometry. This study sheds light on the actual carbon isotope compositions of chlorine-isotopologue pairs of organochlorines, and yields new insights into the real distributions of carbon and chlorine isotopologues. The inconsistent carbon isotope compositions of chlorine-isotopologue pairs are anticipated to benefit the exploration of formation conditions and source identification of organochlorine pollutants., Comment: 27 pages, 4 figures
- Published
- 2019
- Full Text
- View/download PDF