Sensing of volatile organic compounds in indoor atmosphere and confined areas of industrial environments

Abstract

A chemical vapour sensor working with a monochromatic light source and based on optical fibre coated with a thin siloxane polymer film has been developed for in situ monitoring of volatile organic compounds, such as ethylbenzene, xylene (o-xylene), heptane, octane, chloroform, carbon tetrachloride, ethanol and butanol in indoor atmosphere and confined areas of industrial environments. The sensor consists on a monomode optical fibre with an end surface coated with a thin polymeric film by dip-coating technique. The light source utilized was a stabilized laser diode at 1550 nm and the light power changes were measured with a photodiode. The sensor was tested for different VOCs and for different individual concentrations regarding stability, sensitivity, repeatability and reversibility of the analytical signal. The response and desorption time have been found to be 30 seconds and good reproducibility and accuracy have been also obtained. Finally, the analytical performance of the developed sensor was also evaluated and found adequate for actual monitoring on indoor atmospheres.