Effect of Concentration and pH of PBS to the Electrocatalytic Performance of Enzymatic Glucose Biosensor

Phosphate buffer saline (PBS) is commonly applied as an electrolyte for glucose sensor application because ion concentration and osmolality of PBS are similar to the human body. Therefore, it is important to study the effect of concentration and pH of PBS to the electrocatalytic performance of the modified electrode in glucose detection. In this study, the modification of indium tin oxide (ITO) glass electrode by utilizing iron oxide nanoparticles (IONP) coated with citric acid (CA), glucose oxidase (GOx) enzyme and Nafion layer (Nafion/Gox/IONP-CA/ITO) were performed. IONP was prepared by using the precipitation technique through formation of colloidal stable IONP in water at physiological pH. The size of IONP-CA precipitates was ~19 nm with maghemite (γ-Fe 2 O 3 ) phase characterized using transmission electron microscopy (TEM) and X-ray diffraction (XRD), respectively. Increasing the PBS concentration increased the electrocatalytic performance of the bioelectrode whereas pH of PBS buffer solution affected the GOx bioactivity. The modified electrode Nafion/Gox/IONP-CA/ITO displayed good electrochemical and electrocatalytic performance in glucose detection.