On the inappropriate use of gated emission measurements in oxygen quenching studies of luminescent thin film sensors

Data is presented from a comparison of Stern–Volmer studies on oxygen quenching of Pt octaethylporphyrin (PtOEP) luminescence both in fluid solution and encapsulated in ethylcellulose (EC) polymer films, and for PdOEP luminescence in EC, using three different experimental methods: time-resolved nanosecond laser kinetics, true steady-state luminescence, and gated luminescence using a 10 μs pulsed xenon lamp excitation source. While the first two methods give results that are reliable and in good agreement, results obtained using pulsed xenon lamp excitation with emission gating are unreliable because of systematic errors in quantitative emission intensity measurements using this type of apparatus. The sources and effects of these errors are identified and discussed.