CHARACTERIZATION OF CERIUM OXIDE-CHITOSAN NANOCOMPOSITE-MODIFIED SCREEN PRINTED CARBON ELECTRODE AND APPLICATION IN MELATONIN DETERMINATION

A simple and effective modification of the working screen printed carbon electrode (SPCE) surface has been developed with a mixture of chitosan biopolymer and nano cerium oxide at 1: 1 composition for the detection of melatonin, a circadian rhythm regulation hormone. The fabricated electrode was characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrophotometer (EDS), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Electro-oxidation behaviors of melatonin were extensively observed by differential pulse voltammetric(DPV) analysis. The experimental results demonstrated that the modified cerium oxide-chitosan screen printed carbon electrode (SPCE-Chi-CeO2) exhibited satisfactorily improvement in the electrochemical current sensitivity. Alinear calibration curve for melatonin was obtained in the concentration range from 0-10 mu g/ml with a detection limit of 0.18 mu g/ml based on DPV measurement. Good selectivity was also obtained in an interference study with some other closely structural related compounds such as tryptophan and serotonin. Thus this modification strategy was proved to be a suitable tool for the simple, fast, sensitive and selective determination of melatonin.