Electropolymerised platinum porphyrin polymers for dissolved oxygen sensing

Abstract

Fast response optical sensors for oxygen, based on luminescent electropolymerised porphyrin polymers, are described. The sensitivity of the electropolymerised polymers for oxygen detection was found to be dependent on the potential at which the polymers were formed. Results are presented for polymers formed at two different oxidation potentials and for two platinum porphyrins: Pt tetraphenylporphyrin (Pt-TPP) and Pt octaethylporphyrin (Pt-OEP). Sensitivities of the poly-Pt-TPP and poly-Pt-OEP films to dissolved oxygen, given by the Stern–Volmer quenching coefficients, were obtained from luminescence 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 luminescence 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 detection obtained for the Pt-OEP based sensor was 0.06 mg l^–1.