Optical oxygen sensor based on phosphorescence lifetime quenching and employing a polymer immobilised metalloporphyrin probe. Part 1. Theory and instrumentation.

A review of the theory of phosphorescence quenching is given, and its particular application to the sensing of oxygen is outlined. The advantages of measuring phosphorescence lifetime as opposed to phosphorescence intensity are reviewed. The advantages of using the metalloporphyrins as such sensors are identified and in particular the characteristics of palladium coproporphyrin are discussed. The exceptionally long room temperature lifetime of this material makes it possible to use relatively simple PC-based instrumentation to measure lifetimes, with a xenon flashlamp light source. The design of such a system is given and its performance in measuring phosphorescence lifetime in aqueous solutions is demonstrated.