Electrochemical sensing and characterization of denatonium ion by ion transfer at polarized liquid/liquid interfaces

Abstract

Ion transfer electrochemistry is a powerful tool for the study of ionic species in solution. In this paper, square wave voltammetry and chronoamperometry are applied for the quantification and characterization of denatonium ion (N-benzyl-2-(2,6-dimethylphenylamino)-N,N-diethyl-2-oxoethanaminium) in water, an important additive present in commercial products. The method presented is based on the monitoring of the transfer of the cation across a microporous membrane separating an aqueous solution and an organic solution of 1,2-dichloroethane. Calibration curves are built with both techniques and the resulting detection limits and linear ranges of response are discussed. Furthermore, the different performance characteristics of the two techniques are exploited to extract the values of the aqueous diffusion coefficient of the ion denatonium and its standard transfer potential from water to 1,2-dichloroethane. The last parameter is of great importance for the evaluation of the ion lipophilicity, that plays a role in its distribution in living organisms and its impact on biological media.