Three major classes of charge transfer reactions can be studied at an ITIES:
*Ion transfer reactions
*Assisted ion transfer reactions
*Heterogeneous electron transfer reactions
The Nernst equation for an ion transfer reaction reads
where  is the standard transfer potential defined as the Gibbs energy of transfer expressed in a voltage scale.
The Nernst equation for a single heterogeneous electron transfer reaction reads
where  is the standard redox potential for the interfacial transfer of electrons defined as the difference the standard redox potentials of the two redox couples but referred to the aqueous standard hydrogen electrode (SHE).