Optical oxygen sensors based on phosphorescent water-soluble platinum metals porphyrins immobilized in perfluorinated ion-exchange membrane

The cationic complexes of Pt(II), Pd(II) and Rh(III) with two water-soluble porphyrins: meso-tetrakis (4-N-methylpyridyl) porphyrin and meso-tetrakis (4-N,N,N-trimethylaminophenyl) porphyrin are easily and irreversibly immobilized in ion-exchange membranes (e.g. Nafion®). The phosphorescence of the metalloporphyrins inside the membrane is effectively quenched by molecular oxygen. The Stern–Volmer plots (I0/I versus [O2]) are linear over the entire range of oxygen concentrations (0–100%). High photostability, sensitivity and good response times indicate that cationic platinum metals porphyrins immobilized in Nafion® membranes are promising sensing materials for oxygen analysis.