An electrochemical sensor based on poly (L-Cysteine)@AuNPs @ reduced graphene oxide nanocomposite for determination of levofloxacin

A novel electrochemical sensor has been developed for levofloxacin (LEV), by coating a glassy carbon electrode (GCE) with a film of poly (L-Cysteine)@Au NPs@reduced graphene oxide. Cyclic voltammetry, electrochemical impedance spectroscopy, UV-Vis spectroscopy, FT-IR spectroscopy and electron scanning microscope imaging were used for general surface characterization over the successive electrode modification steps. The electro-chemical properties of the LEV was monitored by performing cyclic voltammetry (CV) experiments. The CVs showed one oxidation peak at 1.0 V during the anodic potential scan, which was attributed to LEV. Differential pulse voltammetry experiments using the modified electrode produced linear response in two concentration windows of 1.0 x 10(-11) M and 1.0 x 10(-4) (LEV), with detection limits of 3.0 x 10(-12) M for LEV. The GCE modified through coating with a film of poly(l-cys)/AuNPs/rGO/GCE was found to offer high stability, reproducibility, and repeatability, as well as selectivity for LEV in mixed samples, and was successfully used in the analysis of the LEV in synthetic blood serum, with recovery values of around 99%.