Ferrocene encapsulated lipid and surfactant film on electrode surface: A voltammetric sensor for the determination of trace amounts of thiourea

Abstract

Ferrocene gives well-defined reversible cyclic voltammograms (tris buffer, pH = 7.0), due to ferrocene/ferrocenium couple (inside the phosphatidylcholine and cetyltrimethylammonium¬bromide film) on glassy carbon electrode surface. Both the cathodic and anodic peak currents decrease when thiourea is added to the electrolytic solution, which become undetectable at thiourea concentration 15 μM. The plot of cathodic and anodic current versus concentration of thiourea is linear. The decrease in peak current is proposed to be due to the formation of an electroinactive bridged adduct between thiourea and ferrrocene inside the film. The cyclic voltammogram of ferrocene can be recovered by just immersing the tip of the electrode in a 0.01 mM aqueous potassium ferricyanide solution.