Evanescent-Wave Spectroscopy on Bulk-Response Optode Membranes

Abstract

The absorbance of a solvent polymerie bulk optode membrane in contact with sapphire as a wave-guide is studied with the attenuated total reflection (ATR) technique. Utilizing thin (≤ 1 μm) and, therefore, fast-responding membranes, high values of absorbance are obtained by multiple internal reflection (MIR). The approach has an advantage over conventional transmission studies in that the light beam does not pass through the sample solution. Samp1e-induced swelling of the membrane may, however, create problems.