Table 2.
Summary of the most relevant studies about the stability of organic molecules in the presence of minerals under Martian-like conditions.
| Reference | Sample/Preparation Method | Irradiation Source/Spectral Range | Temperature | Pressure/Atmospheric Composition | Oxidants | In Situ/Ex Situ Analysis | Analytical Techniques |
|---|---|---|---|---|---|---|---|
| Oro & Holzer 1979 [178] | Adenine, glycine, and naphthalene impregnated on powdered quartz at various concentration from 0.01% to 0.2%/Murchison meteorite | Mercury-Xenon lamp/200–300 nm | −10 to 25 °C | 1 mbar N2/various O2-content | None | Ex situ | Ion exchange chromatography for glycine, UV-vis spectrophotometry for adenine, Gas chromatography for naphthalene and Murchison |
| Stoker & Bullock 1997 [177] | Glycine powder mixed with palagonite at 1% concentration | Xenon lamp/210–710 nm | Room temperature | 100 mbar, 95.59% CO2, 4.21% Ar, 0.11% O2, 0.09% CO | None | In situ | Gas chromatography |
| Scappini et al. 2004 [179] | Aqueous suspension of DNA and montmorillonite and kaolinite (20 μg DNA and 2 mg clay in 2 mL water) | Nd:YAG pulsed laser/266 nm | Room temperature | Terrestrial ambient conditions | None | Ex situ | Biological transformation |
| Ciaravella et al. 2004 [180] | Aqueous suspension of DNA and montmorillonite and kaolinite (10 μg DNA and 2 mg clay in 1.4 mL water) | Electron impact X-ray source/Monochromatic X-rays of 1.49, 4.51, and 8.04 keV | Room temperature | Vacuum | None | Biological transformation | |
| Garry et al. 2006 [181] | JSC Mars-1 and Salten Skov Martian soil analogs containing native amino acids | Deuterium lamp/190–325 nm | Room temperature (Experiment I and II)/−63 °C (Experiment III) | 1 × 10−5 mbar (Experiment I and II)/7 mbar CO2 (Experiment III) | None | Ex situ | HPLC |
| Biondi et al. 2007 [182] | Aqueous suspension of RNA and montmorillonite (2.25 × 10−10 moles RNA and 1.3 mg montmorillonite in 75 μL water) | Atlas Germicidal Lamp (15 W)/254 nm | Room temperature | Terrestrial ambient conditions | None | Ex situ | Analysis of self-cleavage activity |
| Shkrob & Chemerisov 2009 [183] | Aqueous suspensions of carboxylic, hydroxycarboxylic, and aminocarboxylic acids, carboxylated aromatics, amino acids, and peptides with anatase, goethite, and hematite | Nd:YAG pulsed laser/355 nm | −196 to −73 °C/22 °C | 1 bar, N2 | None | Ex situ | EPR/transient absorption spectroscopy |
| Shkrob et al. 2010 [184] | Aqueous suspensions of carboxylic, hydroxycarboxylic, and aminocarboxylic acids, carboxylated aromatics, amino acids, and peptides with anatase, goethite, and hematite | Nd:YAG pulsed laser/355 nm | −196 °C | 1 bar, N2 | None | Ex situ | EPR |
| Stalport et al. 2010 [185] | Carboxylic acids α-aminoisobutyric acid (AIB), mellitic acid, phthalic acid, and trimesic acid directly deposited on quartz windows or underneath a layer of JSC Mars-1 | Solar radiation >200 nm | Temperature at low Earth orbit | Pressure at low Earth orbit | None | Ex situ | IR spectroscopy |
| Johnson & Pratt 2010 [186] | Amino acids glycine, L-alanine, L-valine, L-glutamic acid, and L-aspartic acid in metal-rich sulfate brines (1 mM amino acid concentration) | Xenon lamp/250–700 nm | −40 to 20 °C | 7 to 15 mbar, 95.3% CO2, 2.7% N2, 1.6% Ar, and 0.13% O2 | None | Ex situ | XRD, HPLC |
| Johnson & Pratt 2011 [187] | Amino acids L-Alanine, L-valine, L-aspartic acid, L-glutamic acid, and glycine inoculated into I-MAR Martian regolith simulant at 0.01% concentration | Xenon lamp/210–900 nm | −40.4 to 24 °C (on average −17.6 °C) | 10−22 mbar (on average 13.3 mbar), 48.6% CO2, 50% Ar, 1.4% N2, 0.07% O2, 0.04% CO, 0.02% H2O, 0.01% H2 | None | Ex situ | HPLC |
| Shkrob et al. 2011 [188] | Aqueous suspensions of nucleic acid components with anatase, goethite, and hematite | Nd:YAG pulsed laser/355 nm | −196 °C | 1 bar, N2 | None | Ex situ | EPR |
| Fornaro et al. 2013 [168] | Nucleobases adenine, uracil, cytosine, and hypoxanthine adsorbed on magnesium oxide and forsterite at concentrations in the range 0.1–10% | Mercury-Xenon lamp/185–2000 nm | 25 °C | Vacuum (~10−2–10−3 mbar) | None | In situ | Diffuse Reflectance Fourier Transform Infrared (DRIFT) spectroscopy |
| Poch et al. 2015 [172] | Glycine, urea, and adenine co-deposited with nontronite with high molecule-mineral mass ratio (from 1.0 to 3.6) | Xenon lamp/190–400 nm | −55 °C | 6 ± 1 mbar, N2 | None | In situ | IR spectroscopy |
| dos Santos et al. 2016 [189] | 25 amino acids spiked onto augite, enstatite, goethite, gypsum, hematite, jarosite, labradorite, montmorillonite, nontronite, olivine, saponite, and a basaltic lava, at various concentration (approx. 0.001% to 0.1%) | Xenon lamp/200–400 nm | −80 to 20 °C | 6 mbar, 95% CO2, 5% N2 | None | Ex situ | GC-MS |
| Ertem et al. 2017 [190] | Purine, pyrimidine, and uracil impregnated on ferric oxide, calcite, calcium sulphate, kaolinite, and clay-bearing Atacama desert soil at 0.0025% concentration | Xenon lamp/200–400 nm (Experiment I); Gamma Cell 40 from a 137Cs source/Gamma rays 3 Gy (Experiment II) | −196 to 25 °C (Experiment I); 25 °C (Experiment II) | 15–25 mbar/Ambient pressure, 95.3% CO2, 2.7% N2, 0.13 O2 (Experiment I); Ambient pressure, 95.3% CO2, 2.7% N2, 0.13 O2 (Experiment II) | 0.6% NaClO4 | Ex situ | HPLC |
| Fornaro et al. 2018 [67] | AMP and UMP adsorbed on lizardite, antigorite, labradorite, natrolite, hematite, apatite, and forsterite at 5% concentration | Xenon lamp/200–930 nm (Experiment I); Xenon lamp/180–900 nm (Experiment II) | 25 °C (Experiment I); −20 °C (Experiment II) | Terrestrial ambient conditions (Experiment I); 6 mbar CO2 (Experiment II) | None | In situ (Experiment I); Ex situ (Experiment II) | Diffuse Reflectance Fourier Transform Infrared (DRIFT) spectroscopy |