Sensitive voltammetric determination of rifaximin by electrode modified by nanocomposite of MWCNT/MnO2/Au NPs

Antibiotics are a group of antimicrobial compounds that are used in human medicine, aquaculture, and the livestock industry to treat and prevent disease and improve growth. However, improper use of antibiotics may lead to antibiotics entrance in the environment through water and land, which may cause various toxic effects. Therefore, it is necessary to use easy, fast and sensitive methods like electrochemical methods to detect them. Herein, Au-decorated Multi-walled carbon nanotubes (MWCNTs) /MnO2 nanocomposites which seems as a Gypsophila paniculata flower were utilized to detection of Rifaximin (RFX). In this method MWCNT/MnO2 nanocomposites were first drop-casted onto the GCEs then the electro-deposition of Au NPs onto the modified GCEs was done. The formation and electroanalytical performance of the fabricated sensor were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) Spectroscopy, X-ray diffraction (XRD), cyclic and linear sweep voltammetry (LSV). The LSV response of the electrode to RFX was linear in the range 0.75-200 & mu;\M with a detection limit of 0.25 & mu;M, a sensitivity of 0.38 & mu;A & mu;M-1 cm-2 and the relative standard deviation (RSD) of 7.0 % under the optimum conditions. Besides, the RFX is successfully measured in human blood serum and RFX tablet samples, in conditions close to the physiological environment (pH = 6) without any sample pre-treatment. The stability, reproducibility, and repetitive usability exhibited by the fabricated modified electrode are very good to make it a suitable electrochemical sensor for the determination of RFX in pharmaceutical preparations and its quality control and moreover in real samples.