Optical sensing schemes for Prussian Blue/Prussian White film system

Optical chemical sensing schemes exploiting redox properties of Prussian Bl ue/Prusian White him system are reported. Transparent, thin film composed o f Prussian Blue and N-substituted polypyrrole was chemically deposited on n on-conducting polyester foil. The process of the film formation is induced and accelerated by UV radiation. The film is robust, crack-free and strongl y adheres to the plastic support. The film was used as a receptor part of a flow-through detector cell. All spectrophotometric measurements were perfo rmed at the wavelength of 720 nm, i.e. at the absorption maximum of the Pru ssian Blue film. The Prussian Blue/Prussian White film sensor system exhibi ts excellent operational stability and long shelf-life. The Prussian Blue f ilm is shown to be suitable for optical determination of selected strong re ductants. Also potential application of the film for optical determination of alkali cations involved in the redox process is shown. In situ generated Prussian White film is mechanically stable, however, can be easily oxidize d to Prussian Blue form. This feature of the Prussian White film can be app lied for optical determination of various oxidants. It was also shown that the presented detector cell is useful for optical determination of redox sp ecies in non-transparent, turbid samples. The Prussian Blue/Prussian White film redox system offers a new approach to near-infrared optical sensing ap plications. (C) 2000 Elsevier Science B.V. All rights reserved.