Study on organically modified sol-gel sensing membrane for fiber optic oxygen sensor based on phase delay detection

A new kind of organically modified oxygen-sensitive membrane based on fluorescence quenching was prepared by sol-gel method,using dimthyldimethoxysilane(DDS) and tetraethoxysilane(TEOS) as the mixed precursor, Ru(phen)_3Cl_2 as the indicator.The factors influencing the formation of membranes were studied and the effects of the amount of DDS doped in the precursor on the structure and the property of sensing membranes were investigated.The results indicate that the membrane is uniform and crack-free,and has favorable mechanical ability and good flexibility with the proper amount of DDS doped.Base on phase delay detection,the fiber optic oxygen sensor with this sensing membrane has a detection limit of 2×10~(-6) and a response time of less than 30s for the detection of oxygen gas.For the detection of dissolved oxygen,its detection limit is 0.5mg/L and the response time is less than 50s.Compared with pure TEOS sensing membrane,the modified sensing membranes have better reproducibility and stability,and are convenient for the detection of dissolved oxygen.