Analysis of carbon and nitrogen signatures with laser-induced breakdown spectroscopy; the quest for organics under Mars-like conditions

• Published in: Spectrochimica acta. Part B: Atomic spectroscopy 2017-05, Vol.131, p.8-17
• Main Authors: Dequaire, T., Meslin, P.-Y., Beck, P., Jaber, M., Cousin, A., Rapin, W., Lasue, J., Gasnault, O., Maurice, S., Buch, A., Szopa, C., Coll, P.
• Format: Article
• Language: English
• Subjects: Astrophysics; Earth and Planetary Astrophysics; Sciences of the Universe; Solar and Stellar Astrophysics
• ISSN: 0584-8547; 1873-3565
• DOI: 10.1016/j.sab.2017.02.015

Organic matter has been continuously delivered by meteorites and comets to Mars since its formation, and possibly formed in situ by abiogenic and/or biogenic processes. This organic matter may be preserved from the harsh oxidizing environment of Mars in specific locations. Together with water, organic molecules are necessary to the emergence of life as we know it. Since the first martian landers, scientists have been searching for organics and until today, only one positive detection has been made by a Gas Chromatography Mass Spectrometer (GCMS) instrument onboard the Curiosity rover. In this article we investigate a complementary approach to guide the search for organic matter using ChemCam, the first Laser-Induced Breakdown Spectroscopy (LIBS) instrument on Mars. This experimental study focuses on the analysis of carbon and nitrogen LIBS signatures in organoclay samples and allows the determination of the critical level (Lc) and limit of detection (LoD) of these elements with LIBS under Mars-like conditions, giving new insights into the search of organic matter on Mars. [Display omitted] •LIBS presents a potential to detect N-rich environments on Mars.•Nitrogen is a better tracer than carbon to detect adenine molecules in a martian environment by LIBS.•LIBS onboard space mission can select interesting targets containing potentially organic matter.•LIBS can guide dedicated instruments towards organic-rich samples to analyze.