A “green” cellulose paper based glucose amperometric biosensor

A simple low cost “green” biosensor configuration comprising of a hydrophilic cellulose paper disk with immobilised glucose oxidase (GOx) via adsorption step, placed on top of a screen printed carbon electrode (SPCE) was developed. This biosensor configuration allowed for low volume of glucose sample (5 μL) to be analysed. Cellulose paper was also used as the pre-storage reagent matrix for 0.1 M phosphate buffer solution (PBS, pH 7.0) and 10 mM soluble ferrocene monocarboxylic acid mediator. This biosensor exhibited a linear dynamic calibration range of 1 to 5 mM glucose (r2 = 0.971), with a limit of detection of 0.18 mM and retained 98% of its signal after a period of four months. In addition, its performance was demonstrated in the analysis of selected commercial soda beverages. The glucose concentrations obtained by the biosensor corroborated well with an independent high performance liquid chromatographic (HPLC) method.