A key strategy in the search for past or present life in the Solar System is to hunt for organic molecules that are indicative of biological activity. Methods for extracting such molecules have primarily focused on pyrolysis techniques, but this requires samples to be heated and can cause reactions with chemicals native to the target environment. On Mars, for instance, reactions with perchlorate salts can potentially result in the formation of chlorohydrocarbons that are then detected by mass spectrometry. This adds a layer of difficulty in determining the original composition of the sample.

Researchers have reported the use of supercritical carbon dioxide (SCCO2) as an alternative to pyrolysis. The method might allow for the extraction of unaltered native organic species. In their study, the team reported using this technique to extract unaltered amino acids from Mars regolith simulant in the laboratory by capillary electrophoresis laser-induced fluorescence (CE/LIF) and liquid chromatography with mass spectrometry (LC/MS) techniques. This preliminary work could inform future astrobiology missions designed to search for organic molecules on locations like Mars.

The study, “Extraction of amino acids using supercritical carbon dioxide for in situ astrobiological applications,” was published in the International Journal of Astrobiology. The research was supported in part by the Astrobiology Science and Technology for Exploring Planets (ASTEP) element of the NASA Astrobiology Program. ASTEP was an active program element from 2001 to 2014 and supported investigations focused on exploring Earth’s extreme environments to learn how best to search for life on other planets. The types of projects that were funded by ASTEP are now competed under Planetary Science and Technology from Analog Research (PSTAR).