Manganese dioxide (MnO 2 )/Fullerene-C 60 -Modified Electrodes for the Voltammetric Determination of Rifaximin

Rifaximin (RFX) is a broad-spectrum oral antibiotic with bactericidal actions against Gram-negative and Gram-positive bacteria. In the present work, a sensitive voltammetric assay for the RFX in pharmaceutical formulations is designed using nanostructured working electrodes. Surface functionalization with manganese dioxide (MnO 2 )/fullerene-C 60 nanocomposite exhibited the highest electrochemical responses with a sharp oxidation peak at about 336 mV that was obtained using the differential pulse voltammetry (DPV). The cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were applied, while the electrode matrix composition including types of nanomaterials, electroanalytical parameters, and pH effect were optimized. To that end, using the DPV, high sensitivity was obtained from the linear calibration curve ranged from 0.8 to 31.5 µg·mL −1 with the correlation coefficient of 0.99, limit of detection of 0.76 µg·mL −1 and limit of quantification of 2.31 µg·mL −1 . Accordingly, the designed approach is offering a potential applicability towards the RFX determination in pharmaceutical preparations and its quality control.