Which technique is an amperometric method?

• A. Polarography
• B. Potentiometry
• C. pH measurement
• D. pCO2 measurement

Answer: (A)

Amperometric methods detect a signal from the current that flows as a redox reaction occurs at a fixed electrode potential. Polarography is a classic amperometric technique where the potential is swept and the resulting current is recorded to produce a current–potential (polarogram) curve. The measured current, especially in the diffusion-limited region, is proportional to the analyte’s concentration, making this approach ideal for quantitation.

Potentiometry, by contrast, measures the potential difference between electrodes with negligible current and is exemplified by pH measurement. pCO2 measurement is typically not based on current at a fixed potential; it uses other sensing principles, such as pH-based or infrared methods. Thus, polarography stands out as the amperometric method among the options.