Monitoring volatile BTX (benzene, toluene and xylenes) molecules in workplaces: towards a real-time analyzer

Benzene, Toluene and Xylenes (BTX) are known for their toxicity. They can be found in the atmosphere of outdoor and indoor environments. Long exposure to these volatile compounds may have dangerous impacts on human health.
The aim of this work is to develop real-time detecting device based on the pre-concentration of airborne BTX molecules on a material and their simultaneous detecting by ultra-violet spectroscopy in order to monitor the exposition towards BTX in workplace environments. The developed material should have a large specific area and an adapted functionalization to target the BTX molecules in a very complex matrix such as the air. Much research conducted on silica materials has shown the advantages of these materials for monitoring volatile organic compounds. In this view, we have synthesized mesoporous silica nanoparticles material using a modified Stöber process, the templating agent used was cetyltrimethylammonium chloride (CTACl). We added phenyl functions (up to 10% molar – ratio) in order to enhance the selectivity toward BTX molecules. The nanoparticles were assembled on a quartz substrate using drop-coating technique. A 4µm thickness film was obtained and tested in a dedicated laboratory experimental set-up . Interesting results were obtained, reversible adsorption – regeneration cycles were observed on the film. The presentation will summarize the different aspects of the present work and some results obtained with the developed film.