Electropolymerised platinum porphyrin polymers for dissolved oxygen sensing

Fast response optical sensors for oxygen, based on luminescent electropolym erised porphyrin polymers, are described. The sensitivity of the electropol ymerised polymers for oxygen detection was found to be dependent on the pot ential at which the polymers were formed. Results are presented for polymer s formed at two different oxidation potentials and for two platinum porphyr ins: Pt tetraphenylporphyrin (Pt-TPP) and Pt octaethylporphyrin (Pt-OEP). S ensitivities of the poly-Pt-TPP and poly-Pt-OEP films to dissolved oxygen, given by the Stern-Volmer quenching coefficients, were obtained from lumine scence lifetime measurements and were 1.12 (mg l(-1))(-1) and 2.07 (mg l(-1 ))(-1), respectively. The response time, which was determined from luminesc ence intensity measurements, for the poly-Pt-OEP to a step change in oxygen concentration of 4.3 mg l(-1) to 38.6 mg l(-1) was 8 ms. The limit of dete ction obtained for the Pt-OEP based sensor was 0.06 mg l(-1).