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Characterization, Quantification and Compound-specific Isotopic Analysis of Pyrogenic Carbon Using Benzene Polycarboxylic Acids (BPCA)
Published on: May 16, 2016
Carbon, carbides, and methane in an apollo 12 sample.
Science (New York, N.Y.)
|February 5, 1971
Summary
Apollo 12 lunar fines contain indigenous carbon, including carbide and methane. The carbon isotopic composition of lunar carbide is significantly higher than in meteorites, suggesting unique lunar origins.
Area of Science:
- Geochemistry
- Lunar Science
- Isotope Analysis
Background:
- Understanding the origin and composition of lunar volatiles is crucial for lunar exploration.
- Previous studies have identified various carbon species in lunar samples, but their origins remain debated.
Purpose of the Study:
- To determine the total carbon content and isotopic composition of Apollo 12 sample 12023 fines.
- To identify and quantify different carbon-bearing species, specifically carbide and indigenous methane.
- To investigate the origin of lunar carbide through isotopic analysis.
Main Methods:
- Elemental analysis for total carbon content.
- Isotopic ratio mass spectrometry for delta(13)C analysis.
- Chemical hydrolysis with deuterium chloride to differentiate carbon species.
- Vacuum pyrolysis to 1100 degrees C to analyze released gases and their isotopic variations.
Main Results:
- Total carbon content was 110 µg/g, with delta(13)C of +12‰.
- Carbide and indigenous methane were confirmed, present at 7–21 µg/g and ~2 µg/g, respectively.
- Pyrolysis released carbon monoxide, carbon dioxide, and methane, with isotopic variations indicating multiple carbon sources.
- Lunar carbide exhibited a high delta(13)C value of +14‰, distinct from meteoritic carbide.
Conclusions:
- Apollo 12 fines contain indigenous carbon, including carbide and methane.
- The high delta(13)C of lunar carbide suggests it is either indigenous to the Moon or a highly fractionated meteoritic component.
- Further research is needed to fully elucidate the origin of lunar carbon species.
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