on 09-23-201905:33 AM - edited on 11-09-202103:49 AM by usermigration2
Online δ13C analysis of volatile fatty acids in sediment/porewater systems by liquid chromatography-isotope ratio mass spectrometry Verena Heuer, Marcus Elvert, Stefanie Tille, Michael Krummen, Xavier Prieto Mollar, Laura R. Hmelo, Kai-Uwe Hinrichs 1) Organic Geochemistry Group, DFG-Research Center Ocean Margins & Dept. of Geosciences, University of Bremen, P.O. Box 330 440, D-28334 Bremen, Germany, 2) Thermo Electron Corporation, Finnigan Advanced Mass Spectrometry, Hanna-Kunath-Strasse 11, D-28199 Bremen, Germany Limnology and Oceanography: Methods (2006), V4, pp346–357, doi: 10.4319/lom.2006.4.346 Volatile fatty acids (VFAs) are central intermediates of anaerobic metabolism and present in aquatic environments such as marine sediments. Conceptually, the isotopic composition of volatile fatty acids is presumed to be sensitive to the specific biogeochemical processes involved in their production and consumption. However, due to generally low environmental concentrations, our knowledge on isotopic variability of VFAs is limited. We report the development and application of a new protocol for compound-specific carbon isotopic analysis of VFAs in marine porewaters and other aqueous liquids. This new protocol involves reversed-phase separation of volatile fatty acids with an aqueous mobile phase by high performance liquid chromatography (HPLC) combined with chemical oxidation of the effluents by the FinniganTM LC IsoLink interface (Krummen et al. 2004) and subsequent online transfer of the resulting CO2 into an isotope ratio mass spectrometer.