Sol-gel immobilised ruthenium(II) polypyridyl complexes as chemical transducers for optical pH sensing

A range of fluorescent ruthenium(II) polypyridyl complexes have been employ ed in an optical sensor device for pH analysis. The dye materials were immo bilised in a sol-gel glass matrix and characterised upon exposure to aqueou s buffer solutions. Changes of below 0.1 pH units were detectable using the se dye-doped glass films, and linear ranges as large as pH 3-9 were observe d. Sol-gel immobilisation effectively enhanced the operating range of these materials compared to solution. Interference from fluorescence quenching d ue to molecular oxygen was found to place important restrictions on the nat ure of dyes suitable for this application. (C) 2000 Elsevier Science S.A. A ll rights reserved.