A recent study shows that organic solvents could cause carbon contamination in rock samples, particularly with regard to samples that contain low Total Organic Carbon (TOC). Organic solvents were shown to cause changes in total organic carbon (TOC) and stable carbon isotopic composition (δ13C) values for organic matter. TOC and δ13C are important tools used to study the sedimentary rock record, which can provide details about the geological history and evolution of Earth, as well as the history and evolution of our planet’s biosphere.

The team tested a range of solvents and sample types, and determined that ethanol was the only solvent that did not cause noticeable contamination. In fact, the results indicates that ethanol could actually protect against contamination.

The paper, “Bias in carbon concentration and δ13C measurements of organic matter due to cleaning treatments with organic solvents,” was published in the journal Chemical Geology. The work was supported by NASA Astrobiology through the Exobiology Program.