Fibre-optic oxygen sensor based on luminescence quenching of a Pt(II)complex embedded in polymer matrices

The monitoring of the presence of oxygen in a variety of media has become of increasing interest, especially in relation to the modern necessity for effective and reliable environmental studies. With a view to extending the range of oxygen sensors available for this purpose, as well as reducing some of the problems inherent to the use of the existing ones, a new oxygen sensor has been developed based on luminescence quenching of cis-bis[2-(2′-thienyl) pyridine] platinum(II). This orthometallated complex has been selected as it displays a variety of desirable properties required for effective oxygen analysis. It is immobilized on a variety of polymer matrices and their suitability for this application then evaluated. A prototype sensor device has been constructed and calibrated and the signal-to-noise ratio (SNR) and power consumption optimized. With the objective of minimizing the number of reference points required for a reliable calibration plot, several different methods have been tested. One of these methods requires only two points and gives good calibration over the range (0-5)×103 Pa oxygen partial pressure with a precision of 0.7% at 5×103 Pa. A precision of 0.3% at 21.2×103 Pa is achieved using a three-point calibration plot. The prototype construction also compensates to a certain extent for systematic instrumental drifts.