A modified glassy carbon electrode was prepared through electropolymerization of caffeic acid in the presence of either carbon nanotubes or nano‐carbon drop cast onto the electrode surface. The voltammetric behaviour of the electrode was characterized using the ortho‐quinone moiety on the caffeic acid unit and the surface loading optimized for current response. The nanocomposite mediated electrode was used for the sensitive detection of glutathione at concentrations as low as 500 nM.

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The electroanalytical detection of sulfite has been explored at an in situ formed copper ultramicroelectrode array. The protocol is based upon the in situ deposition of copper at a gold ultramicroelectrode array of cubic geometry which consists of 256 ultramicroelectrodes which are 5 microns in radius and are separated from their nearest neighbor by 100 microns. The immobilized copper array is electrocatalytic for the electrochemical reduction of sulfur dioxide which is formed after protonation of sulfite at low pH values (< pH 2). A sensitivity and detection limit of 0.35 nA mM À1 and 6 mM respectively is shown to be possible in pH 2.5 using linear sweep voltammetry with a linear range observed from 20 -500 mM.

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Poly(caffeic acid) polymer was immobilized onto the surface of a glassy carbon electrode via electropolymerization. Voltammetry shows a signal related to the two‐electron oxidation of the immobilized hydroquinone groups in the caffeic acid monomer units. The modified electrode in aqueous solution shows complexation of the electrogenerated o‐quinone species with melamine thus allowing in the electrochemical detection of melamine by recording the shift in potential of the oxidation signal of the polymer. Melamine detection was investigated in pure aqueous solutions and in the presence of milk powder solutions and the proposed analytical method of melamine detection in milk powder was applied successfully with an average recovery of ca. (91±7.9)%.