Role of the Tenax® Adsorbent in the Interpretation of the EGA and GC-MS Analyses Performed With the Sample Analysis at Mars in Gale Crater

Abstract

The Sample Analysis at Mars (SAM) experiment on the National Aeronautics and Space Administration Curiosity rover seeks evidence of organic compounds on the surface of Mars. Since the beginning of the mission, various organic molecules have been detected and identified. While several have been demonstrated to be indigenous to the Martian soil and rocks analyzed, others appear to have been produced from sources internal to the experiment. The objective of this study is to build an exhaustive molecular database to support the interpretation of SAM results by identifying all the chemical species produced from Tenax® adsorbents, by determining (1) the thermal degradation by-products of Tenax®, (2) the effect of Tenax® conditioning on the formation of Tenax® by-products, (3) the impact of MTBSTFA or a mixture of MTBSTFA and DMF on Tenax® decomposition, and (4) the reaction between Tenax® and calcium perchlorate. Our results indicate that the by-products of the SAM trap are due to the impact of trap heating, the impact of the derivatization reagent (MTBSTFA) and the presence of perchlorate in Martian soil. Some of these by-products are observed in the SAM gas chromatograph mass spectrometer data from Mars.