Enhanced surface plasmon resonance sensor performance using reduced graphene oxide (rGO) layers for aflatoxin detection

• The roughness of the rGO layer affects the sensitivity value and performance of the SPR sensor. • The rGO layer produced with a thickness of 339 nm using the spin coating deposition technique produced a sensitivity value of 700.39°/RIU. • SPR sensor performance layer with Au/rGO layer provides an increase in sensor sensitivity compared to other studies such as Meshginqalam from 91.11°/RIU for gold to 120°/RIU with Au/graphene to 700.39°/RIU. • Surface plasmon resonance (SPR) sensing has emerged as a promising alternative due to its high sensitivity compared to molecularly imprinted polymers (MIP), high-performance liquid chromatography (HPLC) and thin layer chromatography (TLC). This study investigates the use of a surface plasmon resonance (SPR) sensor based on the Kretschmann configuration, featuring a gold coating and a reduced graphene oxide (rGO) sensing layer, for detecting low concentrations of aflatoxin B1. A BK-7 prism, coated with a 50 nm thick gold layer, was employed to induce resonance between incident light and the free electrons in the gold. The addition of a reduced graphene oxide layer on top of the gold further enhanced the sensor’s sensitivity. This enhancement is attributed to the reduction of oxygen groups in the rGO, creating vacancy defects that trap the analyte molecules, particularly aflatoxin B1. Experimental results showed a resonance angle shift corresponding to changes in refractive index, yielding a sensitivity of 700.39°/RIU, a linearity value of 0.9005, and a resolution of 0.6228 ppm. These findings suggest that the Au/rGO-coated SPR sensor holds great promise for detecting mycotoxins such as aflatoxin B1, making it suitable for industrial applications.