Experimental Coupling of a MEMS Gas Chromatograph and a Mass Spectrometer for Organic Analysis in Space Environments

The mass spectrometer for planetary exploration (MASPEX) is a versatile mass spectrometer with unprecedented mass resolution designed for spaceflight. However, the current version of MASPEX is designed for continuous sampling during flybys of planetary bodies and does not include gas chromatography, which can improve the analysis of complex mixtures of organic compounds in space environments. Here, micro-electro-mechanical system (MEMS) gas chromatography (GC) linearity, reproducibility, and column analytical performance were first demonstrated prior to the coupling to MASPEX for MEMS GC-mass spectrometer (MS) analyses. Linearity of response was demonstrated for n-hexane over 2 orders of magnitude of on-column mass (concentration). Retention time reproducibility in the MEMS GC was <= 2% relative standard deviation (RSD). MEMS GC column analytical performance calculations showed the average number of theoretical plates, N, and the height equivalent to a theoretical plate, HETP, to be 16 239 (1623 plates per meter) and 0.062 cm, respectively. N defines a chromatographic centroid peak apex divided by the peak width at half height, similar to mass resolution. When coupled to MASPEX, the retention time reproducibility was in a similar range of 1-2% relative standard deviation with a slightly larger deviation seen from the mass spectrometer detector due to start trigger variations with a manual start trigger in the FastFlight software compared to the LabView code used for the MEMS GC-MS testing. The collected mass spectra showed close consistency with National Institute of Standards and Technology (NIST) reference mass spectra providing confidence in chemical compound identification. We present the first data generated from the coupling of these devices.