SURFACE-ACOUSTIC-WAVE OXYGEN SENSOR

A surface acoustic wave (SAW) device that responds to oxygen pressure was developed by coating a 158-MHz quartz SAW device with an oxygen-bi nding agent. Two types of coatings were used. One type was prepared by dissolving an oxygen-binding agent in a toluene solution of a copolym er containing the axial ligand. A second type was prepared with an oxy gen-binding porphyrin in a toluene solution containing excess axial li gand without a polymer matrix. In the polymer-based coatings, the copo lymer served to provide the axial ligand to the oxygen-binding agent a nd as a coating matrix on the surface of the SAW device. The oxygen,se nsing SAW device has been shown to bind oxygen following a Langmuir is otherm and may be used to measure the equilibrium constant of the oxyg en-binding compound in the coating matrix.