Optical oxygen sensor based on phosphorescence lifetime quenching and employing a polymer immobilised metalloporphyrin probe

A gaseous oxygen sensor is described based on the measurement of phosphorescence lifetime of the dye palladium coproporphyrin, immobilised in a range of membrane materials including polyvinyl chloride, polymethylmethacrylate, polystyrene and silicone rubber. The lifetime of the dye in these materials is described, measured using a simple system consisting of a pulsed xenon flash lamp light source and a PC-based data acquisition system. The linearity of the sensing membranes over the 0–100 per cent oxygen range is presented together with data on temperature sensitivity, the effects of CO2, N2O, H2O and halothane, and the effects of ageing over a 90 day period. The sensors based upon polystyrene immobilised dye appear to provide the optimum characteristics for a gaseous oxygen sensor.