摘要

This paper describes the development and optimization of an amperometric bienzymatic biosensor for glucose, based on glucose oxidase (GOX) and peroxidase (HRP), immobilized on mesoporous silica with hexagonal symmetry (MCM-41). The mesoporous material was immobilized by Nafion assisted adsorption on a glassy carbon electrode, which was used as working electrode. Measurements were performed in a conventional three electrode cell using a Ag/AgCl reference electrode and platinum wire as counter electrode. Operating parameters such as GOX/HRP enzyme ratio, mediator (catechol) concentration, applied potential and pH were optimized. The proposed biosensor showed excellent analytical performance with detection and quantification limits of 8.6x10-6 M and 2.5x10-5 M, respectively; analytical sensitivity of 4.67x10-4 AM-1, repeatability %26lt;5?% RSD and a long-term stability of 10 days (5 daily measurements). Also, five possible interferences were studied and only ascorbic acid showed an amperometric signal, which can be removed with 5?% iodine pretreatment. The biosensor was successfully tested for glucose determination in pharmaceutical formulations, and compared well with an established commercial photometric enzymatic kit (Megazyme).

  • 出版日期2013-1