Abstract
An amperometric nonenzymatic dopamine sensor has been developed. Cobalt oxide (Co3O4) nanoparticles were uniformly dispersed inside mesoporous SiO2/C. A sol-gel process was used for the preparation of this mesoporous composite material (SiO2/C). This mesoporous composite has a pore size of around 13-14nm, a large surface area (S-BET 421 m(2)g(-1)) and large porevolume (0.98cm(3)g(-1)) as determined by the BET technique. The material compactness was confirmed by SEM images which showing that there is no phase segregation at the magnification applied. The chemical homogeneity of the materials was confirmed by EDX mapping. The SiO2/C/Co3O4 nanomaterial was pressed in desk format to fabricate a working electrode for nonenzymatic amperometric sensing of dopamine at a pH value of 7.0 and at a typical working potential of 0.25V vs SCE. The detection limit, linear response range and sensitivity are 0.018molL(-1), 10-240molL(-1), and 80AmolL(-1)cm(-2), respectively. The response time of theelectrode is less than 1s in the presence of 60molL(-1) of dopamine. The sensor showed chemically stability, high sensitivity and is not interfered by other electroactive molecules present in blood. The repeatability of this sensor was evaluated as 1.9% (RSD; for n=10 at a 40molL(-1)dopamine level.