Influence of Calcium Perchlorate on the Search for Martian Organic Compounds with MTBSTFA/DMF Derivatization
Yuanyuan He1, Arnaud Buch1, Cyril Szopa2
1Laboratoire Génie des Procédés et Matériaux, CentraleSupélec, University Paris-Saclay, Gif-sur-Yvette, France.
Abstract:
N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA), mixed with the solvent N,N-dimethylformamide (DMF), is used as a derivatizing reagent by the Sample Analysis at Mars (SAM) experiment onboard NASA's Curiosity rover and will soon be utilized by the Mars Organic Molecule Analyzer experiment onboard the ESA/Roscosmos Rosalind Franklin rover. The pyrolysis products of MTBSTFA, DMF, and the MTBSTFA/DMF mixtures, obtained at different temperatures, were analyzed. Two different pyrolysis modes were studied, flash pyrolysis and ramp pyrolysis (35°C/min), to evaluate the potential influence of the sample heating speed on the production of products in space chromatographs. The effect of the presence of calcium perchlorate on the pyrolysis products of MTBSTFA/DMF was also studied to ascertain the potential effect of perchlorate species known to be present at the martian surface. The results show that MTBSTFA/DMF derivatization should be applied below 300°C when using flash pyrolysis, as numerous products of MTBSTFA/DMF were formed at high pyrolysis temperatures. However, when an SAM-like ramp pyrolysis was applied, the final pyrolysis temperature did not appear to influence the degradation products of MTBSTFA/DMF. All products of MTBSTFA/DMF pyrolysis are listed in this article, providing a major database of products for the analysis of martian analog samples, meteorites, and the in situ analysis of martian rocks and soils. In addition, the presence of calcium perchlorate does not show any obvious effects on the pyrolysis of MTBSTFA/DMF: Only chloromethane and TBDMS-Cl (chloro-tertbutyldimethylsilane) were detected, whereas chlorobenzene and other chlorine-bearing compounds were not detected. However, other chlorine-bearing compounds were detected after pyrolysis of the Murchison meteorite in the presence of calcium perchlorate. This result reinforces previous suggestions that chloride-bearing compounds could be reaction products of martian samples and perchlorate.
More Related Videos
06:23Preparation of DMMTAV and DMDTAV Using DMAV for Environmental Applications: Synthesis, Purification, and Confirmation
Published on: March 9, 2018
09:38Single-throughput Complementary High-resolution Analytical Techniques for Characterizing Complex Natural Organic Matter Mixtures
Published on: January 7, 2019
Related Concept Videos
Effects of EDTA on End-Point Detection Methods
In the visual method, metal-ion indicators (metallochromic dyes), which have distinct colors in their free and complex forms, are added to the mixture to signal the titration's end point. They form stable complexes with metal ions, but these complexes are weaker than the corresponding metal–EDTA complexes. As a...
¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)
Gravimetry: Inorganic And Organic Precipitating Agents
Spectroscopy of Carboxylic Acid Derivatives
Precipitation Titration: Endpoint Detection Methods
In the Volhard method, a standard excess of AgNO3 is first added to the...
Mass Spectrometry: Isotope Effect
