A model for the assessment of interfering processes in Faradic electrodes

A model based on the changes of the solid activity due to the transformation of one solid into another is introduced. The model allows to state broad-spectrum equations which describe the behaviour of the potential of second- and third-order Faradic electrodes. Experimental verification of the model was carried out using common metal-based electrodes and also a quite complex thick-film pH sensor. The model was used to predict the redox behaviour in the following cases: (i) study of the potential variation of a Ag/AgBr electrode in the presence of certain amounts of chloride and, (ii) a RuO2-based thick-film pH sensor in front of common anions. There was found a remarkably good agreement between the experimental and theoretical values.