Amperometric Ion Sensing Approaches at Liquid/Liquid Interfaces for Inorganic, Organic and Biological Ions

Abstract

Electrochemistry at the interface between two immiscible electrolyte solutions (ITIES) has become an invaluable tool for the selective and sensitive detection of cationic and anionic species, including charged drug molecules and proteins. In addition, neutral molecules can also be detected at the ITIES via enzymatic reactions. This chapter highlights recent developments towards creating a wide spectrum of sensing platforms involving ion transfer across the ITIES. As well as outlining the basic principles needed for performing these sensing applications, the development of ITIES-based detection strategies for inorganic, organic, and biological ions is discussed.

Electrochemical assessment of a tripodal thiourea-based anion receptor at the liquid|liquid interface

“…However, in the presence of a ligand, the extraction reaction would be dictated by the properties of the ligand and its interaction with the target anion, particularly its ability to replace the solvation shell of the aqueous anion. 31 Complexation of phosphate anions (another anion with tetrahedral geometry) with receptor 1 at the water|DCB interface was also explored. Voltammetric measurements of a 1 M (pH 7) phosphate buffer (aq) |10 mM BTPPATFPB (DCB) in the presence of 1 mM receptor 1 (DCB) provided two reversible peaks within the potential window of the CV (Fig.…”

“…The potential shift depends on the affinity of the ligand for the target ion. For Scheme 1, where the concentration of the anion is much higher than that of the ligand (x c y), the reversible half-wave potential of the facilitated ion transfer reaction (D w o f 1/2 ) is related to the concentration of the anionic species (c A À) (eqn (1)): 20,30,31…”