Modification of Gold Substrate With Fe3O4-Graphene Nanocomposite to Increase Resolution of Surface Plasmon Resonance (SPR) Glucose Sensor

In this study, magnetite (Fe
₃
O
₄
) was composited with graphene (Gr) and used as a non-enzymatic glucose sensor material based of surface plasmon resonance (SPR). The Fe
₃
O
₄
nanoparticles were succesfully synthesized by ultrasonic co-precipitation method while variation composition of composite samples was successfully prepared at room temperature by varying the concentration ratio of graphene and Fe
₃
O
₄
. The resulting composites have good crystallinity and purity with Fe
₃
O
₄
nanoparticles attach on the graphene surface. The commercial gold (Au) chip with a thickness of 50 nm was modified with a composite by depositing the various compositions of the composite on the Au chip surface using a spin coater. The most optimal SPR response was shown by the Fe
₃
O
₄
-Gr (3:1) sample with a shift in resonance intensity of 18.2 r.u in detecting 5 mM of glucose. Moreover, the detection limit of the synthesized sensor reaches 0.1995 mM and has good stability at 20 measurement cycles.