Soluble Organic Compounds and Cyanide in Apollo 17 Lunar Samples: Origins and Curation Effects

We analyzed 12 Apollo 17 samples through the Apollo Next Generation Sample Analysis (ANGSA) program to determine the abundances of a variety of compound classes, including amino acids, aldehydes, ketones, amines, carboxylic acids, and cyanide-releasing species. Analyzed samples included portions of double drive tube 73001/73002, the bottom half of which (73001) was hermetically sealed under lunar vacuum, as well as lunar regolith samples from three different illumination environments that had been curated frozen for ∼50 years. Consistent with previous results, we detected low levels of amino acids in the hot-water extracts of most samples (0.55–12.03 nmol/g in unhydrolyzed samples; 0.53–72.38 nmol/g after acid hydrolysis of the extracts). We also detected one-carbon and two-carbon species of amines, aldehydes, and carboxylic acids (i.e., methylamine, ethylamine, formaldehyde, acetaldehyde, formic acid, acetic acid) not previously reported in lunar samples, as well as insoluble cyanide-forming species. Although these compounds are potential precursor molecules for amino acids, no specific precursor relationships could be determined. Nylon contamination was the likely source of some amino acids. Abundances of some species (e.g., cyanide) decreased with increasing depth in the drive tube, suggesting that exogenous delivery and concentration mechanisms near the surface outweighed surface degradation processes. In addition, we observed the potential cold trapping of volatile amines in the persistently shadowed samples analyzed. Finally, we noted the effects of different curation conditions; hermetic sealing appeared to preserve higher amounts of volatile compounds, while frozen curation did not have a noticeable preservation effect on the organic volatiles analyzed here.