Direct Growth of Carbon Nanotubes on Silver Substrate for Determination of Fluoroquinolone

Abstract

Metallic electrodes modified with carbon nanotubes (CNTs) by direct growth have advantages over the ones modified through external connection methods. These advantages are: (i) reduced contact resistance between CNTs and metal substrate, which is required for electroanalytical determinations. (ii) Strong adhesion of the CNTs layer to the metal substrate which in turn prevents the detachment of CNTs from the electrode surface and stops the deterioration of the signal with time and use. This present work shows the use of carbon nanotubes-modified silver (CNTs-Ag) electrode prepared by direct growth of CNTs as indicator electrodes for differential electrolytic potentiometric (DEP) determination of the fluoroquinolone antibiotic, ciprofloxacin. Characterization of CNTs-Ag electrode by scanning electron microscopy, X-ray diffraction, and Raman spectroscopy showed the growth of aligned, crystalline, and graphitized CNTs. Application of CNTs-Ag electrode for the determination of ciprofloxacin by sequential injection analysis (SIA) method exhibited fast and stable response, reproducible signals, and durability for long-term use. Ciprofloxacin has been quantified in the range of 60 – 1000 µmol/L with a good linear relationship. This work combined the advantages of Direct grown CNTs, SIA technique, and the square-wave DEP method. Figure 1