Curcumin-Cu2+ complex generated on carbon nanotubes for electrocatalytic application toward electrooxidation of hydroxylamine

Abstract

Based on complexation interaction between Cu2+ and curcumin and the π-π stacking interaction between curcumin and single-walled carbon nanotubes (SWNTs), we have described a facile approach to fabrication of curcumin-Cu2+ complex (Cu2+/CM/SWNTs)-modified GC electrodes through simple immersion of the curcumin/SWMTs (CM/SWNTs)-modified GC electrodes into aqueous Cu2+. The Cu2+/CM/SWNTs-modified GC electrodes exhibit highly improved stability and superior electrocatalytic activity toward electrooxidation of hydroxylamine in physiological pH in comparison with the CM/SWNTs-modified GC electrodes. By taking advantage of the efficient electrocatalytic activity of curcumin-Cu2+ complex for hydroxylamine electrooxidation, we have demonstrated the electrocatalytic application of curcumin-Cu2+ complex through development of an electrochemical sensor for hydroxylamine based on the Cu2+/CM/SWNTs-modified GC electrodes. The current response of the electrochemical sensor toward hydroxylamine concentration shows a linear relationship in the dynamic ranges of 1.0–100 µM and 100–1000 µM with a detection limit of 0.019 µM based on 3σ. The electrochemical sensor is repeatable and reproducible with RSD ≤ 4.6% (n = 3) for intra-electrode repeatability and RSD ≤ 4.1% (n = 3 electrodes) for inter-electrode reproducibility. The sensor was successfully used for selective hydroxylamine assay in pharmaceuticals samples including hydroxyurea tables and pralidoxime iodide injections with satisfactory results.