Preparation and properties of modified sol-gel sensing membrane for fiber optic oxygen sensor

Modified sensing membranes based on fluorecence quenching were prepared by the sol-gel method, using formamide as the drying control chemical additive, tetraethoxysilane as the main material, Ru (phen)3 Cl2 as the indicator. The membrane with the optimum thickness of 20–50μm is uniform and crack-free, in which the indicator has a very small leaking rate. The membrane is immersed in water for 50h, the membrane sensing parameter M decreases by less than 5%. The fiber optic oxygen sensor with the sensing membrane has a detection limit of 5×10−6 M (ppm), a response time of less than 30s, excellent reproducibility and stability.