In amperometry, which measurement is determined using this principle?

In amperometry, which measurement is determined using this principle?

• A. pH determination
• B. pCO2 determination
• C. pO2 determination
• D. Sodium determination

Answer: (C)

Amperometry measures the current produced when a species is electrochemically reduced or oxidized at a fixed electrode potential. In practice, measuring oxygen is a classic amperometric application: a Clark-type sensor uses a membrane that lets oxygen diffuse to the working electrode, where O2 is reduced at a set potential. The resulting current is proportional to the dissolved oxygen concentration (pO2) in the sample. Other common measurements are determined by different electrochemical principles: pH is typically read with a glass electrode that generates a potential based on hydrogen ion activity (potentiometry), pCO2 is usually determined by gas methods or calculated from pH and bicarbonate, and sodium is measured with ion-selective electrodes that depend on ion activity (potentiometry).

Amperometry measures the current produced when a species is electrochemically reduced or oxidized at a fixed electrode potential. In practice, measuring oxygen is a classic amperometric application: a Clark-type sensor uses a membrane that lets oxygen diffuse to the working electrode, where O2 is reduced at a set potential. The resulting current is proportional to the dissolved oxygen concentration (pO2) in the sample. Other common measurements are determined by different electrochemical principles: pH is typically read with a glass electrode that generates a potential based on hydrogen ion activity (potentiometry), pCO2 is usually determined by gas methods or calculated from pH and bicarbonate, and sodium is measured with ion-selective electrodes that depend on ion activity (potentiometry).