Solid-State Glucose Sensor Using LaF_3-Based Transducer

A new-type glucose sensor using a LaF_3-based transducer was investigated as the first example of a solid-electrolytecoupled biosensor. The sensor element was composed of the following electrochemical cell: (reference electrode) Sn + SnF_2 | LaF_3 | Pt-glucose oxidase (sensing electrode). The e.m.f. of the sensor cell 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. The 90% response time to 3 × 10^<-2> M glucose was about 15 s at 30℃. The sensitivity of the sensor to glucose was fairly stable for the test period of about 30 days.