ABSTRACT
Ion-transfer voltammetry of organic compounds, including those of biological importance, such as neurotransmitters [1-3], drugs [4-17], pesticides and uncouplers [18, 19], at the interface of two immiscible electrolyte solutions or, in short, the organic solvent or oil-water (O/W) interface has been studied by many authors. These organic com-pounds or drugs are frequently ionizable and present as neutral or charged species or both in physiological-pH media. Thus, the electrochemical or voltammetric study of these organic compounds at the O/W interface should give important information on physicochemical properties of biological interest; the partition coefficients between an organic solvent and water of neutral and charged species and the dissociation con-stants in organic and aqueous media [14-18], which provides a new approach to studying biological effects of drugs, such as the quantitative structure-activity relation-ship, mode of action, and others [20]. Recently, Girault and his coworkers presented a theory of the ionic partition diagram [21, 22]; the ionic partition diagram or lipophilicity profile of drugs as a function of pH and O/W-interfacial potential is constructed on the basis of the transfer potential of related ions, which in turn is derived from the experimental halfwave potential of the ion-transfer voltammogram of drugs at the O/ W interface.
