Changing the direction of ion transfer across o-nitrophenyloctylether∣water interface coupled to electrochemical redox reaction

The electrochemical behaviour of redox probe – t-butylferrocene dissolved in drop of o-nitrophenyloctylether based tetraalkylammonium salt solution, deposited on gold disc or used as a binder of carbon paste electrode, was studied in aqueous solution by cyclic voltammetry and differential pulse voltammetry. The electrochemical generation of t-butylferricinium cation is followed by ion transfer across liquid∣liquid interface: anion insertion into or cation ejection from organic phase, in order to keep neutrality in organic or aqueous phase. It has been shown that apart from hydrophobic–hydrophilic properties of anion present in aqueous phase the direction of ion transfer can be driven by the type of cation present in the organic phase or the geometry of the electrode. The presence of more hydrophobic cation in organic phase or larger distance between electrode∣liquid and liquid–liquid interface promotes anion insertion into organic phase.