IN-SITU SENSING OF VOLATILE ORGANIC COMPOUNDS IN INDOORATMOSPHERE AND CONFINED AREAS OF INDUSTRIAL ENVIRONMENTS

摘要

A chemical vapour sensor working with a monochromatic light source and based on optical fibre coated with thin fluorosiloxane polymer film has been developed for "in situ" monitoring of volatile organic compounds, such as benzene, toluene, chloroform, carbon tetrachloride, and methanol 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 transmitted through the fibre was 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 less than 30 seconds and good reproducibility and accuracy have been also obtained. A mixture of VOCs was also detected and analysed for testing the sensor suitability for use in industrial confined environments.