Selective potentiometric determination of copper(II) ions by use of a molecular deposition film electrode based on water-soluble copper phthalocyanine

A novel copper(II)-selective electrode was produced based on a molecular deposition technique in which water-soluble copper phthalocyanine tetrasulfonate was alternatively deposited with a bipolar pyridine salt (PyC6BPC6Py) on a 3-mercaptopropionic acid modified Au electrode. The potentiometric response is independent on pH of the solution between pH 1 and 5, while it is dependent on the nature of the medium. The electrode has a linear dynamic range between 1 × 10−5 and 0.1 mol 1−1 with a Nernstian slope of 29 mV/decade concentration and a detection limit of 7 × 10−6 mol 1−1 in acetate buffer (0.2 mol 1−1, pH 4.5). Except for Fe2+, Fe3+ and Co2+, other common inorganic cations do not interfere in the determination of copper(II). The electrode has the advantages of low resistance, short conditioning time and fast response.