Optical chemical sensing based on thin films of Prussian Blue

The potential applications of films of Prussian Blue for optical chemical s ensors are investigated. The films are chemically deposited on a non-conduc tive support, mechanically stable, thin, homogenous and optically transpare nt. The maximum of the absorption is observed at 720 nm and is fully compat ible with semiconductor light sources. Strong reductants cause discoloratio n of the him. This effect can be used for optical determination of reductan ts such as ascorbic acid. The film is also suitable for optical determinati on of pH because the absorption spectra undergo reversible changes in the p H 5-9 range. (C) 1998 Elsevier Science S.A. All rights reserved.