Automated Capillary Electrophoresis System Compatible with Mul-tiple Detectors for Potential In Situ Spaceflight Missions

The in situ search for chemical signatures of life on extraterrestrial worlds requires automated hardware capable of performing detailed compositional analysis during robotic missions of exploration. The use of electrophoretic separations in this search is particularly powerful, enabling analysis of a wide range of soluble organic compounds potentially indicative of life, as well as inorganic compounds that can serve as indicators of habitability. Yet to detect this broad range of compounds with a single electrophoresis instrument, a combination of different detection modes is required. For detection of any ionizable species, including organic compounds that do not participate in terrestrial biology (i.e “unknown unknowns”), mass spec-trometry (MS) is essential. Inorganic ions, or any dissolved charged species present, can be analyzed using capacitively cou-pled contactless conductivity detection (C4D). Additionally, for the trace analysis of compounds of key interest to astrobiol-ogy (particularly amino acids), laser-induced-fluorescence (LIF) detection holds unique promise, due to the fact that it has the highest demonstrated sensitivity of any form of detection. Here, we demonstrate a fully automated, portable capillary elec-trophoresis analyzer that is capable of all these modes of detection. The prototype system developed here addresses the three most significant challenges for doing electrophoretic separations: precise sample injection, HV isolation, and automation of all operational steps. These key challenges were successfully addressed with the use of custom-designed rotor-stator valves with optimized operational sequences incorporating gas purging steps, rinses, and HV application.