Graphene/Poly(vinylferrocene) Composite Based Amperometric Biosensor for L-lysine Determination

A novel and sensitive amperometric biosensor for L-lysine determination based on a glassy carbon electrode (GCE) modified with graphene (GR) and redox polymer poly(vinylferrocene) (PVF) was constructed. L-lysine--oxidase was immobilized onto the modified GCE by a glutaraldehyde/bovine serum albumin cross-linking procedure. SEM, CV and EIS were used for the characterization of the surface morphology and stepwise fabrication processes of PVF/GR composite. Optimal composition of the biosensor and experimental conditions that affect the performance of the biosensor are discussed. The effect of buffer pH on biosensor response was studied in detail over a wide pH range. L-lysine biosensor displayed a linear range of 9.9x10(-7) - 3.1x10(-4) M with a low detection limit of 2.3x10(-7) M and K-M(app) value of 0.4mM. The L-lysine biosensor was tested using pharmaceutical sample and cheese with satisfactory results.