DETECTION OF PROPANE BY IR-ATR IN A TEFLON-CLAD FLUORIDE GLASS OPTICAL FIBER

The detection of propane with the use of ATR spectroscopy at 3.3 μm, as the gas diffuses through the Teflon cladding of a fluoride optical fiber, is reported. A theoretical expression for the time-dependent absorbance of the fiber sensor as a function of diffusion coefficient and cladding dimensions is developed. The experimental data fitted to the model give a diffusion coefficient of 8.85 × 10-14 m2 s-1 for propane in Teflon. The potential of the technique for remote or distributed sensing of hydrocarbons is discussed.