Development and Integration of an Ultraminiaturized Gas Chromatograph Prototype Based on Lab-on-a-Chip Microelectromechanical Systems for Space Exploration Missions

Abstract

We developed, integrated, and tested an ultraminiaturized gas chromatograph prototype for space applications based on microelectromechanical system (MEMS) preconcentrator, column, and detector subunits. The fluidic interface, the mechanical design, and the electronic system were all designed to be easily transposable to space instrumentation. The response linearity, reproducibility as well as the preconcentrator, column, and detector performances were demonstrated using a mixture of n-pentane, n-hexane, benzene, and toluene. Using the column, the response linearity of the nano-gravimetric detector (NGD) was observed over 1 to 2 orders of magnitude with a high R² value of 0.99. The retention time reproducibility was evaluated with a variation lower than 0.2%. The column separation performances were also qualified in terms of number of theoretical plates (N) and height equivalent to a theoretical plate (HETP) with 8275 ± 45 plates (equivalent to 1655 ± 9 plates per meter) and 0.6 mm on average, respectively. The preconcentrator performance for trapping and desorption was also validated. The NGD showed high sensitivity, and the limit of detection was evaluated to be about 3.1 pmol for toluene, which is very suitable for space exploration. The analytical performance of the first μGC-MEMS prototype was already satisfying and adapted for space studies. Nevertheless, some ways of optimization were identified (like back-flush injection for the preconcentrator or the use of valves more suited to space applications) to improve both performances and instrument robustness, and they will be tested in the future with a second version of our prototype.