An electrochemical aptasensor based on gold nanoparticles dotted graphene modified glassy carbon electrode for label-free detection of bisphenol A in milk samples

• Aptamer biosensor for BPA based on label-free electrochemical determination.
• Simple and easy to use for small size molecules assays.
• GNPs/GR nanocomposites were used as effective sensing platform.
• Method demonstrated successful quantification of BPA in milk samples.

A simple and label-free electrochemical aptasensor for bisphenol A (BPA) determination was developed based on gold nanoparticles dotted graphene (GNPs/GR) nanocomposite film modified glassy carbon electrode (GCE). The electrochemical probe of ferricyanide was used to investigate the interactions between aptamer and BPA. The resulting GNPs/GR layer exhibited good current response for BPA detection. The highly conductive and biocompatible nanostructure of GNPs/GR nanocomposite was characterised by atomic force microscope (AFM), scanning electron microscopy (SEM) and cyclic voltammetry (CV). The peak current change (ΔI) of ferricyanide was linear with the concentration of BPA in the range from 0.01 μM to 10 μM with the detection limit of 5 nM. The proposed aptasensor is rapid, convenient and low-cost for effective sensing of BPA. Particularly, the aptasensor was applied successfully to determine BPA in milk products, and the average recovery was 105%.