In electrochemistry, ITIES is an acronym for the " interface between two im miscible electrolyte solutions". Usually, one electrolyte is an aqueous electrolyte composed of hydrophilic ions such as NaCl dissolved in water and the other electrolyte is a lipophilic salt such as tetrabutylammonium tetraphenylborate dissolved in an organic solvent immiscible with water such as nitrobenzene, or 1,2-dichloroethane.
An ITIES is an electrochemical interface that is either polarisable or polarised. An ITIES is said polarisable if one can change the Galvani potential difference, or in other words the difference of inner potentials between the two adjacent phases, without noticeably changing the chemical composition of the respective phases (i.e. without noticeable electrochemical reactions taking place at the interface). An ITIES system is said polarised if the distribution of the different charges and redox species between the two phases determines the Galvani potential difference.