Ion Transfer Voltammetry of Azulene Sulfonates at a Liquid|Liquid Interface

Azulene sulfonates with different alkyl groups were examined by ion transfer voltammetry at a nitrobenzene vertical bar water interface. All of the 8 azulene sulfonates showed reversible voltammograms of the monoanion. The parameters of hydrophobicity (standard potentials and standard Gibbs energies of transfer) of the azulene sulfonates were estimated from the mid-point potentials of the voltammograms. Those standard Gibbs energies of transfer were compared with the percentages of ulcer inhibition. As the hydrophobicity increased, the percentage of ulcer inhibition became higher. But the most hydrophobic ion gave the lowest anti-ulcer activity, probably because of the very low solubility in water and the accumulation in membrane.