Bias in carbon concentration and delta13C measurements of organic matter due to 
cleaning treatments with organic solvents

Muller, Élodie; Thomazo, Christophe; Stüeken, Eva E.; Hallmann, Christian; Leider, Arne; Chaduteau, Carine; Buick, Roger; Baton, Franck; Philippot, Pascal; Ader, Magali

doi:10.1016/j.chemgeo.2018.06.018

アイテム詳細

登録内容を編集ファイル形式で保存

一時保存へ追加

タグ情報を表示リリース履歴を表示詳細要約

公開

学術論文

Bias in carbon concentration and delta¹³C measurements of organic matter due to cleaning treatments with organic solvents

MPS-Authors

/persons/resource/persons104837

Hallmann, Christian
Research Group Organic Paleo-Biogeochemistry, Dr. C. Hallmann, Max Planck Institute for Biogeochemistry, Max Planck Society;

/persons/resource/persons86908

Leider, Arne
Research Group Organic Paleo-Biogeochemistry, Dr. C. Hallmann, Max Planck Institute for Biogeochemistry, Max Planck Society;

External Resource

There are no locators available

Fulltext (restricted access)

There are currently no full texts shared for your IP range.

フルテキスト (公開)

公開されているフルテキストはありません

付随資料 (公開)

There is no public supplementary material available

引用

Muller, É., Thomazo, C., Stüeken, E. E., Hallmann, C., Leider, A., Chaduteau, C., Buick, R., Baton, F., Philippot, P., & Ader, M. (2018). Bias in carbon concentration and delta¹³C measurements of organic matter due to cleaning treatments with organic solvents. Chemical Geology, 493, 405-412. doi:10.1016/j.chemgeo.2018.06.018.

引用: https://hdl.handle.net/21.11116/0000-0003-EA96-C

要旨

Interpreting the organic carbon content (TOC) and stable carbon isotopic composition (δ13C) of organic matter in the sedimentary rock record depends on our capability to accurately measure them, while excluding sources of
contamination. This however becomes increasingly problematic as we analyze samples with ever-lower organic
carbon content. Accordingly, organic solvents are sometimes used to remove contaminating traces of modern
organic matter from ancient rock samples. However, especially for very low TOC samples, traces of solvents or
their impurities remaining in the sample may contribute a significant organic contamination that can impact the
bulk measurements of both TOC and δ13C values. This study, including three independent investigations performed
in different laboratories, is the first detailed examination of the effect of cleaning treatments on the
reliability of TOC and δ13C values in a range of natural rock samples and synthetic materials with low TOC
content from below detection limit to 3330 ppm. We investigated the four most common organic solvents used to
remove modern organic matter: dichloromethane (DCM), n-hexane, methanol and ethanol, and evaluated the
effect of grain size and mineralogy. We find that (i) cleaning treatments with methanol, n-hexane and dichloromethane
contaminate rock samples when used directly on sample powder, regardless of the grain size; (ii)
this pollution buffers the natural variability and homogenizes the δ13C values of samples around the isotopic
composition of the solvent, i.e. between −27 and −29‰; (iii) the extent of contamination depends on the
solvent used, DCM being the most contaminating (up to 6000 ppm) and ethanol the only solvent that does not
seem to contaminate rock samples above our detection limit; (iv) sample mineralogy also exerts an influence on
the extent of contamination, clay minerals being more prone to adsorb contaminants. We conclude that the
response of carbon concentrations and the stable carbon isotopic composition of organic matter in geological
samples to cleaning treatments is neither negligible nor systematic when investigating samples with low carbon content.