Multi-Element Sol-Gel Derived Integrated Optic Chemical Sensor

This paper summarizes the development of a self-referenced, multi-channel, integrated optic chemical sensor technology for in-line monitoring of water quality in NASA's water revitalization subsystem, in the controlled ecological life support system for prolonged space missions. The technique uses commonly available materials and straightforward processing to produce channel waveguides in a porous glass, each channel treated with a fluorescence or absorbance based indicator that responds optically to metal ions in water. The porosity of the glass allows metal ions present in water to diffuse into the glass and interact with immobilized indicators, producing a measurable optical change.