New Developments in an Automated Capillary Electrophoresis System Compatible with Multiple Detectors for Potential In Situ Spaceflight Missions

The search for signs of extraterrestrial life requires automated instruments capable of performing remote measurements during in situ missions of exploration. Assessing the chemical composition of an extraterrestrial environment may provide information to several lines of evidence. Due to the complexity expected in such a sample, the use of separation steps to sort out the target groups of analytes prior to detection is a key step. In this context, capillary electrophoresis (CE) is a particularly powerful separation technique that enables the analysis of a wide range of soluble organic compounds associated to life as we know it, as well as inorganic compounds that can serve as indicators of habitability. We have recently developed an automated CE system [1] compatible with multiple detectors. This prototype is based on custom-designed rotor-stator valves that allowed overcoming CE specific challenges: precise sample injection, HV isolation, and automation of all operational steps. The performance of this prototype was demonstrated by coupling it to (i) mass spectrometry (MS) to target a broad class of organic compounds and additional capability to identify potential unknown compounds; (ii) contactless conductivity detection (C4D) for measuring inorganic ions and other dissolved charged species [2,3]; and (iii) laser-induced-fluorescence (LIF) for the sensitive analysis of amino acids [4]. During the development of this system we identified some limitations during injection of sample into the capillary that prevented achieving the maximum performance, especially for LIF detection. Here we present how we have now overcome these limitations to allow hydrodynamic injection without sacrificing the simplicity and functionality of rotor-stator valves. In addition, we have also enhanced the capability of the system by enabling up to three-fold capillary multiplexing. This unique feature opens the possibility of having a single instrument with three different detectors (one in each capillary) or using all three capillaries in a single configuration for redundancy (to reduce single point failure). References: [1] Zamuruyev et al. (2021) Anal Chem [2] Ferreira Santos et al. (2018) Electrophoresis [3] Jaramillo et al. (2021) Electrophoresis [4] Creamer et al. (2017) Anal Chem *MSF and KZ contributed equally