Long-Term Thermal Stability of Reagents for Capillary Electrophoresis Analysis on Future Spaceflight Missions

Abstract

A primary goal of future astrobiology missions is the search for the chemical signs of life beyond Earth. Biosignatures indicative of biology can take the form of complex organic molecules or distributions of smaller molecules such as amino acids. To acquire evidence of this second class of biosignatures, separation science is essential. Moreover, when examining polar compounds, liquid-based analysis becomes imperative. Capillary electrophoresis is a powerful liquid-based separation technique ideally suited for the analysis of polar molecules and flight implementation. This technique requires the use of a variety of chemicals, including water, organic solvents, chiral selectors, buffers, and fluorescent dyes. All these chemicals must survive a range of conditions over the multiyear journey to the planetary target of interest. Hence, it is essential to validate that they will function properly after long-term storage in these environments. Here, we demonstrate this for reagents required for capillary electrophoresis analysis coupled with multiple detection systems. Accelerated aging of reagents was performed to simulate storage conditions at 55 °C for 15 years to match possible timelines for future missions to ocean worlds. Following aging, possible chemical alteration of the reagents was interrogated by NMR. Finally, aged reagents were used to perform capillary electrophoresis analysis, and results were compared with those from experiments using fresh reagents. Results indicate that all reagents can perform successful capillary electrophoresis analysis after exposure to thermal conditions equivalent to transport under relevant flight-mission durations (up to 15 years).