(Invited) Capillary Electrophoresis Instrumentation and Methods for Spaceflight Missions of Exploration

The search for evidence of life beyond Earth is among the highest level goals in planetary exploration. However, despite multiple orbiter and landed missions to extraterrestrial bodies in the solar system, we still haven’t found evidence of life. A powerful approach in this search involves seeking biochemical signatures of life at the molecular level, as distributions of organic molecules. The separation techniques capillary electrophoresis (CE) and its miniaturized version, microchip electrophoresis (ME) overcome the limitations of gas-phase techniques and hold unique promise in the search for signatures of life on other worlds. These techniques offers high resolution separations of molecules dissolved in water and are the simplest of all liquid separation methods to implement for flight. Here we describe CE and ME instrumentation developed at JPL and the steps we are taking to someday enable the its implementation on other worlds. Although multiple detection methods can be coupled to CE and ME, we focus on three detection modes: laser-induced fluorescence (LIF) for state-of-the-art measurements of amino acids, mass spectrometry (MS) for broad detection of ionizable organics, and contactless conductivity detection (C4D) for measurements of inorganic and organic ions. These techniques are complementary of each other and would allow full characterization of the chemical composition of a sample in situ. We are not only developing instrumentation but also analytical methods that could be implemented on a mission scenario. Here we also describe a system we dub The Chemical Laptop, which would provide the sample processing capabilities required for in situ analysis on extraterrestrial destinations with ultra-high sensitivity in a compact, low-mass, and low-power package. The Chemical Laptop is a truly portable, battery-powered, automated, and reprogrammable microchip electrophoresis instrument coupled to laser-induced fluorescence detection. This instrument concept could be adapted to the environmental requirements of a variety of astrobiologically interesting targets like Europa, Enceladus, or Titan. This system also serves as a general prototype that could be reprogrammed for terrestrial-based analyses as well.