High Performance Electrochemical Biosensor for Bisphenol A Using Screen Printed Electrodes Modified with Multiwalled Carbon Nanotubes Functionalized with Silver-Doped Zinc Oxide

This study reports on a novel electrochemical biosensor for the detection of Bisphenol A (BPA) using a carbon-screen printed electrode modified with multiwalled carbon nanotubes that are functionalized with silver doped zinc oxide nanoparticles (Ag-ZnONPs) on which laccase enzyme was immobilized. The nanocomposite was characterized in stages by UV-visible, Fourier Transform Infrared Spectroscopy, scanning and transmission electron microscopes. The synthesized hybrid Ag-ZnONPs were spherical in shape with an average size of 20 nm. The surface of Lac/Ag-ZnO/MWCNTs/C-SPE was also characterized using electrochemical methods. The presence of laccase on the surface of the nanocomposite-modified electrode reduced the charge transfer resistance of the redox couple and thereby improved the sensitivity towards the oxidation of Bisphenol A. The catalytic activity was further evaulated with 80 mu M solution by cyclic voltammetry. Under optimum conditions, the biosensor displayed outstanding performance for BPA with a linear range 0.5-2.99 mu M (R-2 > 0.9943) and a limit of detection (LOD) of 6.0 nM. Furthermore, this proposed lacasse biosensor is more selective and stable with a high reproducible response factor (RSD of 0.86%), and was able to adequately quantify BPA in plastic bottle samples. In the light of our results, the biosensor showed promising and trustworthy analytical performance that is ideal for routine sensing applications for BPA in plastic bottles. [GRAPHICS] .