Orateur
Description
Gas chromatography is a widely used analytical technique in space exploration for the separation and identification of organic compounds in complex samples. Space missions impose stringent constraints on onboard instrumentation, which must be as compact, lightweight, and low-power consuming as possible. In this context, ultra-miniaturized chromatographs based on lab-on-chip represent a promising technology for future space missions. Consequently, we developped a lab-on-chip gas chromatograph based on MEMS (Micro Electro Mechanical Systems) technology. Each analytical component (preconcentrator, column, detector) for the gas chromatograph is fabricated on silicon chips and integrated onto a fluidic interface adapted for space requirement, with the aim of achieving performant analysis of planetary samples. This work will focus on the preconcentrator unit, which is a critical part of space gas chromatographs used for in situ analysis. Solid samples are usually pyrolyzed over a given period of time and the preconcentrator is mandatory to focalize the analytes during the sampling phase, and then to inject them at the head of the chromatographic column after a thermal-desorption step. Toachieve this, the preconcentrator is integrated onto a printed circuit boards (PCB) allowing its thermal heating and temperature monitoring. To evaluate the analytical performance of MEMS preconcentrators filled with TENAX TA® as an adsorbent, analytical tests were carried out by coupling the preconcentrators to a commercial gas chromatograph. Two preconcentrators were characterized. One was packed with the adsorbent and stored for two years before testing, while the other was freshly packed with the adsorbent before the experiments. These two preconcentrators were tested to study the effect of time on their adsorption capacity and aging. To evaluate the performance of these preconcentrators, several tests were carried out, including the optimization of adsorption and desorption conditions, as well as breakthrough curve studies. These results demonstrated promising performance in line with our objectives. Both preconcentrators exhibited good linearity between the desorbed number of analytes and the injected one with with R2 > 0.991, while the freshly packed preconcentrator showed a higher adsorption capacity. The use of new adsorbent materials for the sample preconcentrator will also be investigated in order to extend the range of compounds that can be tested. This work shows that we have a component with good analytical performance. The next step will be to continue its qualification for use in space applications.