2.3. Measurement of standard glucose solutions using the
sensor
First, the sensor was soaked in 100 ml of 0.1M phosphate
buffer solution (pH 7.0) in a state of oxygen saturation to fill the
needle-type hollow container with buffer solution. Once sensor
output had stabilized, the sensor was placed in a test tube containing
one of the standard glucose solutions (3.6–18.0 mg dl−1)
to measure changes in concentration of dissolved oxygen inside
the hollow container due to oxidization by glucose oxidase. The
glucose oxidase-sensing scheme involves the employment of
glucose oxidase according to:
D-glucose + O2
glucose oxidase −→ D-gluconolactone + H2O2
To clean the hollow container, the sensor was again placed in
100 ml of buffer solution in a state of oxygen saturation, and the
sensorwas placed in another test tube once output had stabilized.
The above procedures were repeated to measure levels of glucose
in each standard glucose solution.