Characterization of carbon nanotubes-gold nanoparticles composite film modified electrode and voltammetric determination of mefenamic acid

Abstract

A novel carbon nanotubes modified electrode was fabricated, which was based on multi-walled carbon nanotubes (MWCNTs) dispersed in gold nanoparticles (AuNPs) colloid. It was observed that MWCNTs were dispersed in AuNPs colloid homogenously. Dihexadecyl hydrogen phosphate (DHP) was added into the suspension to prepare a more stable film modified electrode. The film showed net structure and had good electron-transfer function. On the composite film coated electrode, the electrochemical behavior of mefenamic acid was studied and an irreversible anodic peak was obtained, which was much larger than that on a bare glassy carbon electrode (GCE), due to the co-effect of MWCNTs and AuNPs on the electrochemical oxidation of mefenamic acid. Under the optimized conditions the anodic peak current was linear to the concentration of mefenamic acid in the range of 1.0 × 10-7 to 2.0 × 10-5 mol L -1. The detection limit was estimated to be 1.0 × 10 -8 mol L-1 after 120 s preconcentration. The method was applied successfully to the determination of mefenamic acid in medicine sample. ©2008 Sociedade Brasileira de Química.