Polycyclic aromatic hydrocarbon analysis with the Mars organic analyzer microchip capillary electrophoresis system

Area of Science:

• Astrobiology
• Analytical Chemistry
• Planetary Science

Background:

• The Mars Organic Analyzer (MOA) is a portable microchip capillary electrophoresis (CE) instrument.
• MOA was initially developed for sensitive amino acid analysis on Mars.
• Polycyclic Aromatic Hydrocarbons (PAHs) are important biomarkers for extraterrestrial life detection.

Purpose of the Study:

• To adapt and optimize the MOA instrument for the detection and analysis of PAHs.
• To establish the viability of MOA for in situ planetary exploration of PAHs.

Main Methods:

• Optimized microchip capillary electrophoresis (CE) separation method for hydrophobic PAHs.
• Utilized a specific separation buffer: 10 mM sulfobutylether-beta-cyclodextrin, 40 mM methyl-beta-cyclodextrin, 5 mM carbonate buffer (pH 10) at 5°C.
• Analyzed laboratory standards, environmental samples, and a Martian analogue sample.

Main Results:

• Achieved baseline separation of a seven-PAH extraterrestrial standard and two terrestrial PAHs.
• Demonstrated limits of detection for PAHs ranging from 2000 ppm to 6 ppb.
• Identified six specific PAHs (including diphenylanthracene, anthracene, and benzo[ghi]fluoranthene) in a Martian analogue sample at ppm levels.

Conclusions:

• The optimized MOA method is effective for PAH analysis.
• MOA is a viable instrument for detecting PAHs in extraterrestrial samples during in situ planetary exploration.