Separation and characterization of marine dissolved organic matter (DOM) by combination of Fe(OH)3 co-precipitation and solid phase extraction followed by ESI FT-ICR MS
Marine dissolved organic matter (DOM) constitutes a major carbon pool in the global carbon cycle. Characterization of its chemical composition will improve our understanding of its role in global biogeochemical cycles. Currently, solid phase extraction (SPE) followed by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analysis has become a powerful approach to characterize the molecular composition of DOM. However, some components in marine DOM, such as highly oxygenated tannin-like molecules, were lost during the SPE process. In this study, a sequential combination of co-precipitation and SPE procedure was proposed to improve the yield of marine DOM extraction. Ferric hydroxide was used as the co-precipitation agent to separate marine DOM, and SPE was carried out for the extraction of DOM from dissolved and precipitate fractions. The total yield in total organic carbon (TOC) and the number of assigned molecules of SPE-DOM increased by 25% and 51%, respectively, compared with those by direct SPE process. The combined process has good selectivity on tannin-like compounds. The result is instructive for the understanding of DOM molecular composition and potential for a routine method for DOM extraction from environmental water samples, especially for marine DOM containing a small amount of tannin-like compounds.
KeywordsDissolved organic matter Co-precipitation SPE FT-ICR MS
This work was supported by the National Key Research and Development Program of China (2018YFA0605800).
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Conflict of interest
The authors declare that they have no conflict of interest.
- 7.Miller MP, McKnight DM. Comparison of seasonal changes in fluorescent dissolved organic matter among aquatic lake and stream sites in the Green Lakes Valley. J Geophys Res Biogeosci. 2010;115(G1):91–103.Google Scholar
- 18.Zhang HF, Zhang YH, Shi Q, Hu JY, Chu MQ, Yu JW, et al. Study on transformation of natural organic matter in source water during chlorination and its chlorinated products using ultrahigh resolution mass spectrometry. Environ Sci Technol. 2012;46(8):4396–402. https://doi.org/10.1021/es203587q.CrossRefGoogle Scholar
- 21.Sleighter RL, Hatcher PG. Molecular characterization of dissolved organic matter (DOM) along a river to ocean transect of the lower Chesapeake Bay by ultrahigh resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. Mar Chem. 2008;110(3):140–52.CrossRefGoogle Scholar
- 25.Li Y, Fang Z, He C, Zhang Y, Xu C, Chung KH, et al. Molecular characterization and transformation of dissolved organic matter in refinery wastewater from water treatment processes: characterization by Fourier transform ion cyclotron resonance mass spectrometry. Energy Fuel. 2015;29(11):6956–63.CrossRefGoogle Scholar
- 26.Shi Q, Hou D, Chung KH, Xu C, Zhao S, Zhang Y. Characterization of heteroatom compounds in a crude oil and its saturates, aromatics, resins, and asphaltenes (SARA) and non-basic nitrogen fractions analyzed by negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. Energy Fuel. 2010;24(4):2545–53.CrossRefGoogle Scholar