RESEARCH ARTICLE Development of an Amperometric-Based Glucose Biosensor to Measure the Glucose Content of Fruit

An amperometric enzyme-electrode was introduced where glucose oxidase (GOD) was im-mobilized on chitosan membrane via crosslinking, and then fastened on a platinum working electrode. The immobilized enzyme showed relatively high retention activity. The activity of the immobilized enzyme was influenced by its loading, being suppressed when more than 0.6 mg enzyme was used in the immobilization. The biosensor showing the highest re-sponse to glucose utilized 0.21 ml/cm2 thick chitosan membrane. The optimum experimen-tal conditions for the biosensors in analysing glucose dissolved in 0.1 M phosphate buffer (pH 6.0) were found to be 35°C and 0.6 V applied potential. The introduced biosensor reached a steady-state current at 60 s. The apparent Michaelis-Menten constant (KappM) of the biosensor was 14.2350 mM, and its detection limit was 0.05 mM at s/n> 3, determined experimentally. The RSD of repeatability and reproducibility of the biosensor were 2.30% and 3.70%, respectively. The biosensor was showed good stability; it retained ~36 % of ini-tial activity after two months of investigation. The performance of the biosensors was evalu-ated by determining the glucose content in fruit homogenates. Their accuracy was compared to that of a commercial glucose assay kit. There was no significance different be-tween two methods, indicating the introduced biosensor is reliable