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Lanthanum Fluoride (LaF3) has been one of the choices as solid
electrolyte when the sensors are studied by means of
electroche- mistry. It has good ion conductivity at room
temperature, stable performace and the insolubility in water.
Because of its insolu- bility, one can design the sensors to
measure some materials in aqueous solution which makes its
biomedical application possible. In our research, the solid
electrolyte is produced by pressing the powder of lanthanum
fluoride, the working electrode is pro- duced by firing thick
film platinum paste, and the reference electrode is
produced by sintering the mixture of tin and tin fluoride
powder. Two copper wires are fixed by silver glue onto working
and reference electrodes respectively. Glucose oxidase ( GOD)
is immobilized on the surface of working electrode. Finally ,a
thin layer of polyvinyl acetate is coated outside the glucose
oxidase to complete the manufacture of the glucose sensor. The
response time of the sensor to oxygen of different partial
pressure from 0 to 1 atm at 26℃ is 36 minutes. The
improvement of the structure of the working electrode (such as
the improve- ment of the sintering to make it more porous)
may shorten the response time. The response time of
individual glucose concen- tration in PBS from 5x10■ to 5x10■
M at 26℃ is reduced to ab- out 5 minutes. It might due to the
reaction of hydrogen ions in the aqueous solution. The
stability of the sensor under our stu- dies can be obtained
at room temperature. The sensitivity to sucrose, galactose,
ascorbic acid and hydrogen peroxide also discussed in the
report. The ion conductivity of lanthanum flu- oride is under
consideration.
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