Abstract
A potentiometric glucose sensor based on the glucose oxidase immobilized on iron ferrite (Fe3O4) nanoparticles/chitosan composite modified gold coated glass substrate was fabricated. The electrode has advantages of both the inorganic Fe3O4 magnetic nanoparticles and the organic substance chitosan. The freshly prepared iron ferrite magnetic nanoparticles were characterized by X-ray diffraction (xRD) and transmission electron microscopy (TEM) technique was used for the analysis of dispersed iron ferrite magnetic nanoparticles in the mixture of glucose oxidase and chitosan. The electrostatic interaction of Fe3O4 nanoparticles with chitosan and the glucose oxidase molecules was investigated by the infra-red reflection absorption spectroscopy (IRAS) study. The glucose oxidase enzyme was immobilized on the surface of iron ferrite/chitosan composite without the use of Nafion or cross linker molecules. The fabricated glucose sensor has shown acceptable potentiometric response for the wide range of glucose concentrations from 1.0 x 10(-6) to 3.0 x 10(-2) M. The sensor electrode showed a sensitivity of 27.3 +/- 0.8 mV/decade and also fast response time of 7.0s. Moreover, the present glucose sensor has demonstrated good reproducibility, repeatability, selectivity and the storage stability. All the obtained results indicated that the glucose sensor based on the glucose oxidase immobilized iron ferrite/chitosan composite modified gold coated glass electrode can be used for the monitoring of glucose concentrations in human serum, drugs and may be applicable to detect glucose in the presence of other analytes.