FIBEROPTIC 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 bec ome of increasing interest, especially in relation to the modern neces sity for effective and reliable environmental studies. With a view to extending the range of oxygen sensors available for this purpose, as w ell as reducing some of the problems inherent to the use of the existi ng ones, a new oxygen sensor has been developed based on luminescence quenching of cis-bis[2-(2'-thienyl)pyridine]platinum(II). This orthome tallated complex has been selected as it displays a variety of desirab le properties required for effective oxygen analysis. It is immobilize d on a variety of polymer matrices and their suitability for this appl ication then evaluated. A prototype sensor device has been constructed and calibrated and the signal-to-noise ratio (SNR) and power consumpt ion optimized. With the objective of minimizing the number of referenc e points required for a reliable calibration plot, several different m ethods have been tested. One of these methods requires only two points and gives good calibration over the range (0-5) X 10(3) Pa oxygen par tial pressure with a precision of 0.7% at 5 X 10(3) Pa. A precision of 0.3% at 21.2 X 10(3) Pa is achieved using a three-point calibration p lot. The prototype construction also compensates to a certain extent f or systematic instrumental drifts.