Supercritical CO₂ and Subcritical H₂O Analysis Instrument: Automated Lipid Analysis for In Situ Planetary Life...

Area of Science:

• Astrobiology
• Planetary Science
• Analytical Chemistry

Background:

• Detecting extraterrestrial life requires sensitive methods for low-concentration biosignatures.
• Traditional methods like GC-MS struggle with certain analytes, needing derivatization.
• Space missions need compact, robust, and automated instrumentation.

Purpose of the Study:

• Introduce the Supercritical CO2 and Subcritical H2O Analysis (SCHAN) instrument.
• Demonstrate its capability for detecting lipid biosignatures relevant to life detection.
• Highlight its suitability for spaceflight applications.

Main Methods:

• Integration of supercritical fluid extraction (SFE) and supercritical fluid chromatography (SFC) with mass spectrometry (MS).
• Utilizes supercritical CO2 with water additive, eliminating need for derivatization and cosolvents.
• Portable and automated system weighing 6.3 kg.

Main Results:

• Achieved efficient lipid biosignature separations.
• Median detection limits of 10 pg/g (ppt) for fatty acids and 50 pg/g (ppt) for sterols.
• Detected free fatty acids and cholesterol in biologically lean Atacama Desert samples.

Conclusions:

• The SCHAN instrument is a compact, portable, and spaceflight-compatible tool.
• It offers an improved method for analyzing organics for astrobiology missions.
• Demonstrates potential for in situ detection of extant or extinct life.