Online wet oxidation/isotope ratio mass spectrometry method for determination of stable carbon isotope ratios of water‐soluble organic carbon in particulate matter

• Published in: Rapid communications in mass spectrometry 2018-10, Vol.32 (19), p.1668-1674
• Main Authors: Suto, Nana, Kawashima, Hiroto
• Format: Article
• Language: English
• Subjects: Carbon; Carbon isotopes; Isotope ratios; Isotopes; Mass spectrometry; Organic carbon; Organic compounds; Oxidation; Particulate emissions; Pretreatment; Quantitative analysis; Scientific imaging; Spectroscopy; Wet oxidation
• ISSN: 0951-4198; 1097-0231
• DOI: 10.1002/rcm.8240

Rationale Water‐soluble organic carbon (WSOC) is formed by oxidation of organic compounds in particulate matter (PM) and accounts for 25–80% of the organic carbon in PM. Stable carbon isotope ratio (δ13C) analysis is widely used to identify the sources of PM, but determining the δ13C values of WSOC is complicated and requires a time‐consuming pretreatment process. Methods We have developed an online wet oxidation/isotope ratio mass spectrometry method with a reduced pretreatment time. We have measured the δ13C values of WSOC by using this method. Results The method showed high accuracy (0.1‰) and precision (0.1‰) for levoglucosan, and the limit of detection was sufficiently low for WSOC analysis. Using this method, we determined δ13C values of WSOC in PM2.5 samples collected in Japan during the period from July to November 2017 and found that the values ranged from −26.5‰ to −25.0‰ (average, −25.8‰). Conclusions Our simple, low‐blank method could be used for rapid quantitative analysis of the δ13C values of WSOC in PM2.5. We propose that this online method be used as a standard method for δ13C analysis of WSOC.