NEW TYPE BIOSENSOR USING SOLID ELECTROLYTE

A LaF3 based-transducer was introduced into enzyme sensors as the first examples of solid electrolyte coupled biosensors. The sensor elements were composed of the following electrochemical cell: (reference electrode) Sn+SnF2|LaF3 (solid electrolyte) |enzyme-immobilized Pt (or Pd) (sensing electrode). When the glucose oxidase-immobilized Pt electrode was used, EMF was found to vary logarithmically with a change in glucose concentration in the range from 2×10-5 to 1×10-2 M in a phosphate buffer solution of pH 6.9. Substitution of Pd for Pt gave similar behavior but the output signal was less dependent on glucose concentration. With the Pt electrode, 90% response time to 3×10-2 M glucose was about 15 s at 30°C, and the glucose sensitivity was fairly stable for the test period of one month. The sensor using the uricase-immobilized Pd electrode was found to respond fairly well to uric acid in the concentration range from 5×10-5 to 5×10-5 M. © 1990.