Simultaneous voltammetric and amperometric determination of morphine and codeine using a chemically modified-palladized aluminum electrode

In the present paper the use of Prussian blue film modified-palladized aluminum electrode (PB/Pd-Al) prepared by a simple and rapid electroless method for the determination of codeine (CO) and morphine (MO) is described. In the first part of the work the oxidation of CO and MO at the modified electrode was investigated by cyclic voltammetry. The electro-oxidation pathway for the both two compounds in the neutral medium (pH 6) was suggested. In optimum conditions the hydrodynamic amperometry was used for the determination of CO and MO at the μM concentration level. It is found that the calibration graphs of CO and MO are linear in the concentration ranges 2–30 and 2–50 μM, respectively. The detection limit of the method was about 0.8 μM. The possibility of using differential pulse voltammetry as well as hydrodynamic amperometry for simultaneous determination of CO and MO at a mixture solution is demonstrated.