Synthesis of PDDA Functionalized Reduced Graphene Oxide Decorated with Gold Nanoparticles and Its Electrochemical Response toward Levofloxacin

In this work synthesis of water-dispersible reduced graphene oxide (rGO), decorated with gold nanoparticles (AuNPs), was carried out in the presence of poly(diallyldimethylammonium chloride) solution (PDDA). The as-prepared hybrid nanocomposite (Au/PDDA/rGO) was characterized using various surface, structural, and electrochemical analysis techniques, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and voltammetry. The electrochemical performance of Au/PDDA/rGO-modified glassy carbon electrode (GCE) was investigated by studying the voltammetric behavior with different concentrations of levofloxacin (LV). Under optimized experimental conditions, at the Au/PDDA/rGO/GCE it was found that the response is linearly proportional to the concentration of LV in the ranges of 1.0 × 10−5–2.0 × 10−4 and 2.0 × 10−4–8.0 × 10−4 mol L−1, with detection limit estimated to be 3.9 × 10−6 mol L−1. The fabricated sensor was successfully applied for determination of LV in pharmaceutical tablets. Additionally, investigation of the interaction between LV and RNA molecules has also been carried out.