A comparative analysis of LIBS emissions in organic compounds of interest in astrobiology under a Mars simulated atmosphere, T. Delgado, J. Fortes, L.M. Cabalín, J.J. Laserna, Microchemical Journal, submitted (14 Feb 2022)

Abstract

In this work, a comparative analysis based on the molecular emission featured by a set of organics compounds of interest in astrobiology has been accomplished by laser-induced breakdown spectroscopy (LIBS). To simulate the real conditions in the red planet, LIBS analysis were performed under a Mars simulated atmosphere. The methodology described in this paper is intended to reveal new insights concerning the influence of the surrounding atmosphere on the molecular emission of organics.Although the atomization of organic compounds is essentially complete at high laser irradiance, the formation routes of new molecules by recombination processes can be appropriately achieved at optimized temporal conditions. In this sense, characteristic atomic and molecular species (C, H, C₂, CN, NH, OH and CH) were inspected in organic compounds of interest in astrobiology. For comparative purposes, LIBS analysis were performed in both air and Martian atmosphere. In addition, statistical analysis (linear discriminant analysis) suggested that differentiating among materials was feasible. Although the use of atomic lines (C, H) only contributes a mere ~62% to the discriminating analysis, the percentage of discrimination was considerably increased (up to 99%) by the progressive introduction of the molecular bands in the DFA analysis, thus confirming the significant contribution of molecular information to the final sorting performance.