Switching between voltammetry and potentiometry in order to determine H+
or OH ion concentration over the entire pH scale by means of tungsten disk
electrode
This study demonstrates that tungsten rotating disk electrode can be used for pH or H+
/OH concentration
measurements in practically entire pH range, using the combination of voltammetric and potentiometric
techniques. In strong acidic (c(H+
) > 103 mol dm3
), and alkaline (c(OH) > 103 mol dm3
)
solutions, rotating tungsten disk electrode can be used as a maintenance-free electrode for voltammetric
determination of H+ and OH ion concentration. After an appropriate electrochemical oxidation, the same
electrode, in a stationary regime, may be used as a potentiometric sensor in the range 3 < pH < 11, with
the response 49.5 ± 2.3 mV per one pH unit.
2011