Which glucose method can employ a polarographic oxygen electrode?

Which glucose method can employ a polarographic oxygen electrode?

• A. Hexokinase
• B. Glucose oxidase
• C. Glucose dehydrogenase
• D. o-Toluidine

Answer: (B)

The test is about whether the measurement uses oxygen as part of the reaction that the electrode monitors. In the glucose oxidase method, glucose is oxidized by the enzyme with oxygen acting as the electron acceptor, producing gluconic acid and hydrogen peroxide. A polarographic oxygen electrode (a Clark-type electrode) measures changes in oxygen concentration or the current associated with oxygen reduction. Because this method directly involves oxygen consumption in the enzymatic step, it can be read with a polarographic oxygen electrode, linking the electrode signal to glucose concentration. The other methods don’t rely on oxygen consumption and are detected by different means: the hexokinase pathway generates NADH and is typically measured photometrically; glucose dehydrogenase methods use NAD+ or other cofactors and are read by absorbance or non-oxygen electrochemical methods; and the o-toluidine approach is a colorimetric chemical reaction, not an electrode-based oxygen measurement.

The test is about whether the measurement uses oxygen as part of the reaction that the electrode monitors. In the glucose oxidase method, glucose is oxidized by the enzyme with oxygen acting as the electron acceptor, producing gluconic acid and hydrogen peroxide. A polarographic oxygen electrode (a Clark-type electrode) measures changes in oxygen concentration or the current associated with oxygen reduction. Because this method directly involves oxygen consumption in the enzymatic step, it can be read with a polarographic oxygen electrode, linking the electrode signal to glucose concentration.

The other methods don’t rely on oxygen consumption and are detected by different means: the hexokinase pathway generates NADH and is typically measured photometrically; glucose dehydrogenase methods use NAD+ or other cofactors and are read by absorbance or non-oxygen electrochemical methods; and the o-toluidine approach is a colorimetric chemical reaction, not an electrode-based oxygen measurement.