Gold-coated silver capsule for elemental analyzer-isotope ratio mass spectrometer: Robust against pretreatment of rock material for organic carbon and δ13C analyses

Fujisaki et al., 2016, 2018, 2019). To prepare the samples for OC analysis with EA-IRMS, coexisting carbonate minerals need to be removed to ensure accurate and precise quantification. For example, for a sediment sample that contains 1 wt% OC and 1 wt% carbonate derived C, the total C would be 2 wt% and the δCtotal C of the non-acidified (non-decalcified) sample would be about –11‰, since the δCorg of a typical pelagic sediment is about –22‰ while the δCcarbonate of benthic foraminifera is about 0‰. In this case, the δCtotal C value cannot be used as a proxy for the δCorg. Several approaches have been proposed for removing carbonate minerals, such as acid treatment using either hydrochloric, phosphoric, or sulfurous acid (Al-Aasm et al., 1990; Brodie et al., 2011) and the stepwise combustion method (Uchida et al., 2008). Acid treatment can be Gold-coated silver capsule for elemental analyzer-isotope ratio mass spectrometer: Robust against pretreatment of rock material for organic carbon and δ13C analyses