Selective detection of hydrocarbon vapors by ATR-leaky mode spectroscopy

The technique of dynamic ATR-leaky mode spectroscopy is demonstrated for polymer films on 50 nm Ag layers. For the vapor series R OH with R equals H,CH3, C2 H5 and the BTX compounds benzene, toluene and the 3 xylene isomers two different ways of obtaining selective sensor detection are described. The first approach uses the specific sensitivity. Each vapor has a specific molecular polarizability which causes a specific sensitivity. The second approach takes advantage of the dynamic method. The specific diffusion of the particular molecule in the polymer matrix can be evaluated. In this context the characteristic diffusion of the 3 isomers of xylene are investigated.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.