Ligand influence in electrocatalytic properties of Cu(ii) triazole complexes for hydrogen peroxide detection in aqueous media

In this work, electrocatalytic changes of Cu(ii) triazole complexes (Cu(L)(2)) resulting from inductive effects were evaluated to fabricate a sensor for hydrogen peroxide (H2O2) determination. Three copper(ii) complexes with electronically differentiated ligands were synthesized by slow diffusion method and characterized by X-ray crystallography, Fourier transformed infrared (FTIR), UV-Vis, scanning electron microscopy (SEM) and voltammetry cyclic (CV). Cu(L-OMe)(2)/GC, Cu(L-Br)(2)/GC and Cu(L-NO2)(2)/GC sensors were then prepared. Under optimal conditions (pH = 11), the optimal sensor presented a response at -0.5 V, good linear range of 1-32 mu M, reproducibility (1.7%), repeatability (1.2%), LOD of 0.0246 mu M (S/N = 5), LOQ of 0.0747 mu M (S/N = 5) and selectivity. Additionally, Cu(L-NO2)(2)/GC sensor has been successfully applied in commercial substances, such as mouthwash, milk and tea.