Compound-specific δ18O analyses of neutral sugars in soils using gas chromatography-pyrolysis-isotope ratio mass spectrometry: Problems, possible solutions and a first application
Publikation: Beitrag in Fachzeitschrift › Forschungsartikel › Beigetragen › Begutachtung
Beitragende
Abstract
Although gas chromatography-pyrolysis-isotope ratio mass spectrometry (GC-Py-IRMS) has allowed us to make online compound-specific δ18O measurements for about the last ten years, this technique has hardly been applied. We tested different pyrolysis reactor designs using standards (vanillin, ethylvanillin, a fatty acid methyl ester and alkanes) in order to optimize the GC-Py-IRMS δ18O measurements. The method was then applied to methylboronic acid (MBA) sugar derivatives (pentoses, 6-deoxyhexoses and hexoses). Plant- and microbial-derived monosaccharides were extracted hydrolytically from litter and topsoils before derivatization. The measured δ18O values of samples and co-analyzed reference material were first drift-corrected by use of regularly discharged pulses of CO reference gas. Secondly, they were corrected for the amount dependence of the δ18O values. Thirdly, the δ18O values were calibrated using the reference material (principle of Identical Treatment'), and, finally, a correction was applied by taking the hydrolytically introduced and water-exchangeable oxygen atoms into account. Our results suggest that the δ18O values of plant-derived monosaccharides in litter reflect the climatic conditions of the last year, whereas δ18O values of the respective topsoils reflect the averaged climate signal of the last decades or even centuries. This demonstrates the high potential of the method for palaeoclimate reconstructions.
Details
Originalsprache | Englisch |
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Seiten (von - bis) | 3522-3532 |
Seitenumfang | 11 |
Fachzeitschrift | Rapid Communications in Mass Spectrometry |
Jahrgang | 23 |
Ausgabenummer | 22 |
Publikationsstatus | Veröffentlicht - Nov. 2009 |
Peer-Review-Status | Ja |
Externe IDs
PubMed | 19844972 |
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