In Situ Real-Time Quantitative and Qualitative Monitoring of Molecular Contamination

摘要

The quantitative and qualitative monitoring of contamination is an important issue for the mitigation of the risks induced by contamination. In situ and real-time measurements of contamination levels are currently performed with good accuracy by using quartz microbalances. However, they have to be completed by chemical analyses to identify the nature of the contaminants. Unfortunately, in situ techniques are limited to a very rough characterization. A transfer of the samples is then required, which prohibits real-time monitoring and may lead to the partial degradation of the samples. To tackle this challenge, an experimental technique, coupling thermogravimetric analysis and mass spectrometry, has been developed at ONERA. This method takes advantage of a preseparation of the species through the thermogravimetric analysis. A numerical tool was moreover developed to process automatically experimental thermogravimetric analysis/mass spectrometry data. It enables determination of the contribution of each species (deconvolution of thermogravimetric analysis measurements species by species, both for quartz crystal microbalance measurements and mass spectrometry spectra) and extraction of the mass spectrum of each of these species. The results of this analysis are presented for the characterization of an adhesive widely used for space applications. The deconvolution in species matches very well the experimental data.