摘要
We present a novel method to measure the C-13/C-12 isotope ratio (reported as delta C-13) of individual, intact bacteriohopanepolyols (BHPs) using semi-preparative ultrahigh pressure liquid chromatography (UPLC) followed by high temperature gas chromatography-isotope ratio mass spectrometry (HT-GC-IRMS). The method is reproducible, as indicated by the precision of delta C-13 values for bacteriohopanetetrol (BHT) extracted from R. palustris biomass and analyzed across an order-of-magnitude range of IRMS peak areas (delta C-13 = -33.4 +/- 0.6 parts per thousand VPDB, n = 94, +/- 1 sigma). To show that this method successfully separates individual BHPs from complex environmental matrices, we report delta C-13 values for BHT and the BHT stereoisomer (BHT-II) from a ca. 2.9 Ma, organic-rich Mediterranean Sea sediment sample. These analyses suggest that intact BHP delta C-13 measurements can greatly improve the interpretation of environmental signals by alleviating the need for side-chain cleavage which reduces BHP source-specificity.
- 出版日期2018-9