Graphite-Epoxy Electrodes Modified with Functionalised Carbon Nanotubes and Chitosan for the Rapid Electrochemical Determination of Dipyrone

A rapid electrochemical procedure for the determination of dipyrone was successfully developed at a carbon nanotube modified graphite-epoxy resin composite (GrEC) electrode. The composite electrode was used as support on which multi-walled carbon nanotubes (MWCNT) were immobilised by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide together with N-hydroxysuccinimide (EDC-NHS) in a chitosan (Chit) matrix. The electrochemical behaviour of dipyrone at this electrode in different buffer electrolytes with pH values between 5.0 and 8.0 was explored using cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy, and comparison with a conventional glassy carbon electrode was made. Dipyrone was best determined by differential pulse voltammetry with a low limit of detection of 1.4 microM. Application to commercial samples was demonstrated.