Fabrication, Characterization and Development of a Modified Poly(Bromocresol Purple/Multiwalled Carbon Nanotubes) Carbon Paste Electrode for the Determination of Sulfanilic acid

A sensitive electrochemical sensor was assembled by the electropolymerization of bromocresol purple on the surface of multiwalled carbon nanotubes modified carbon paste electrode i.e., poly(BC/MWCNTs)CPE. The surface network of the newly constructed electrochemical sensor was recorded by scanning electron microscope. The developed sensor has demonstrated improved electrocatalytic activity towards sulfanilic acid detection in presence of 0.1 M phosphate buffer solution at pH 7.5. The experimental parameters including the effect of scan rate, buffer pH and analyte concentration were optimized systematically. A linear relationship was found between the peak currents and analyte concentrations with limit of detection and limit of quantification values 0.98×10-7 M and 3.2×10-7 M respectively, which are significantly lower than the reported methods. The kinetic parameters such as reaction rate constant (ks), charge transfer coefficient (α), total number of electrons transferred (n) were evaluated and found to be 0.269, 3.27 and 2.0 respectively. The results deduced that the modified poly(BC/MWCNTs)CPE provides high sensitivity, good stability, excellent catalytic activity and better reproducibility along with lower limit of detection for the analysis of sulfanilic acid.