A nanocomposite consisting of reduced graphene oxide and electropolymerized β-cyclodextrin for voltammetric sensing of levofloxacin.

A glassy carbon electrode (GCE) was modified with a nanocomposite prepared from polymerized β-cyclodextrin (β-CD) and reduced graphene oxide (rGO). The modified GCE is shown to enable the voltammetric determination of traces of levofloxacin (LEV) by various electrochemical techniques. Experimental factors affecting the results including the amount of the substrates in preparation of the nanocomposite, accumulation time, the scan rate and pH value of the electrolyte were optimized. The modified GCE, best operated at a working potential of 1.00 V (vs. Ag/AgCl), has two linear response ranges, one for low LEV concentrations (100 pmol L-1 to 100 nmol L-1), and one for higher LEV concentrations (100 nmol L-1 to 100 μmol L-1). The limit of detection and sensitivity are calculated to be 30 pmol L-1 and 467.33 nA μmol L-1 cm-2, respectively. The modified GCE demonstrates a number of advantages such as high sensitivity and selectivity, low LOD, excellent reproducibility, high surface-to-volume ratio, and good electrocatalytic activity towards LEV. The sensor was successfully applied to the determination of LEV in spiked human serum samples. Graphical abstract.