Comprehensive 2-Dimensional Gas Chromatography coupled to a Time-of-Flight Mass Spectrometer for broad-spectrum organic analysis on Mars

An analytical chemistry suite for in-situ broad-spectrum analysis of organic compounds on the Martian surface will be presented. The purpose is to identify nature and abundance of organic components in solid sample material. The instrument uses pyrolysis extraction followed by a comprehensive 2-dimensional gas chromatograph (2DGC) coupled to a Time-of-Flight mass spectrometer (TOFMS). The 2DGC consists of a serial arrangement of two columns connected by a thermal modulator. The first column with a non-stationary phase separates components based primarily on their volatility, whereas the second column with a polar stationary phase separates the sample material based on the polarity. The thermal modulator is a resistively heated and liquid cooled wall coated capillary tube made out of stainless steel. The TOFMS uses electron impact ionization with orthogonal ion acceleration, a reflectron and a multi-channel plate detector. We will present the instrument design for the laboratory prototype, focusing on a discussion of the critical instrument components. We will show experimental results of Martian analogous Earth soil samples. These samples yield a chromatographic peak capacity of more than 1000 peaks. These are displayed as highly structured chromatograms. Qualitative identification of sample constituents can be derived from homologous series standards. These results are further verified via the TOFMS system. By coupling the 2DGC to a TOFMS, quantitative and mass spectrometric information is available for each data point in the chromatogram. This design will allow us to remotely analyze Martian soil samples to determine the presence, nature and abundance of organic materials.