Selection of Chemical Adsorbents and Operating Conditions for the Injection Traps of the Gas Chromatograph on Board the Dragonfly Mass Spectrometer

The Dragonfly mission is set to explore Titan’s surface in the mid-2030s. This relocatable lander is equipped with the Dragonfly Mass Spectrometer (DraMS) instrument. One of DraMS functioning mode is gas chromatography–mass spectrometry, to identify organic compounds in solid samples. DraMS-GC includes two independent chemical injection traps to focus the molecules released from the sample. Initially, Tenax TA was planned to be the adsorbent in the injection traps because of its heritage in previous space probes. However, Tenax TA has shown some decomposition products that challenge the identification of the molecules indigenous to the sample. In this work, the performance of another adsorbent powder, Carbotrap C, was compared to Tenax TA. Performance was evaluated in DraMS-like desorption conditions by comparing the recovery yield after adsorption and desorption of a set of 53 organic compounds of interest to Titan. Recovery with Carbotrap C was either similar or better than with Tenax TA for 79% of compounds. This recovery yield was further improved by increasing the desorption temperature. DraMS low desorption flow rate appears to be the most limiting parameter for recovery. Desorption from both Tenax TA and Carbotrap C led to partial but comparable racemization for three of the four amino acids that were enantiomerically resolved. Together, these results led to the integration of Carbotrap C in one of the DraMS injection traps.