The electrode used for pCO2 determination is sensitive to which of the following?

The electrode used for pCO2 determination is sensitive to which of the following?

• A. pH change
• B. pCO2 change
• C. pO2 levels
• D. Temperature

Answer: (A)

The pCO2 electrode works by sensing changes in hydrogen ion concentration, not by measuring CO2 gas directly. CO2 diffuses through a gas-permeable membrane into an internal solution where it forms carbonic acid, lowering the pH. This pH change is what the electrode detects and converts into a signal from which pCO2 is inferred. So, the electrode is most sensitive to pH change because that is the actual signal generated by CO2 diffusion. Temperature can affect readings and other factors like pO2 don’t drive the measurement, but the primary detectable effect is the shift in pH caused by CO2.

The pCO2 electrode works by sensing changes in hydrogen ion concentration, not by measuring CO2 gas directly. CO2 diffuses through a gas-permeable membrane into an internal solution where it forms carbonic acid, lowering the pH. This pH change is what the electrode detects and converts into a signal from which pCO2 is inferred. So, the electrode is most sensitive to pH change because that is the actual signal generated by CO2 diffusion. Temperature can affect readings and other factors like pO2 don’t drive the measurement, but the primary detectable effect is the shift in pH caused by CO2.