Amperometric determination of carbon dioxide using a gold electrode modified by the underpotential‐deposited cadmium

An underpotential‐deposited cadmium layer formed on a gold electrode was used to amperometrically determine PCO₂ in an aqueous medium. This electrode reduces nitrate anions in an aqueous solution. The reduction current produced can be related to the proton concentration. Thus, when dissolved CO₂ is present in a nitrate solution it alters the proton concentration, which can then be measured amperometrically. Experimental investigation of this system and a Nafion coated gold electrode were both carried out. The effect of oxygen present in the system is also discussed.