Novel optical trace oxygen sensors based on platinum(II) and palladium(II) complexes with 5,10,15,20-meso-tetrakis-(2,3,4,5,6-pentafluorphenyl)-porphyrin covalently immobilized on silica-gel particles

New optical sensors for trace amounts of oxygen are based on platinum(II) and palladium(II) complexes of 5,10,15,20-meso-tetrakis-(2,3,4,5,6-pentafluorphenyl)-porphyrin covalently attached to the surface of amino-modified silica-gel particles. The dye-doped silica-gel particles are dispersed in silicone rubber. The Stern-Volmer plots show linear response and are virtually identical for either luminescence intensity and decay time. Other features include high photostability and rapid response times (similar to 150 ms in gas phase). The sensors based on the palladium(II) complex show significantly higher sensitivity (K(SV) about 67 kPa(-1) at 25 degrees C) with the dynamic range from 0.02 to 100 Pa. The sensitivity of the platinum(II) complexes is significantly lower (K(SV) =3.7-4.2 kPa(-1), dynamic range 0.3-1000 Pa). The sensors can be suitable for application in breweries, water boilers and for marine research (monitoring of oxygen minimum zones). (C) 2011 Elsevier B.V. All rights reserved.