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

Abstract

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 μM, reproducibility (1.7%), repeatability (1.2%), LOD of 0.0246 μM (S/N = 5), LOQ of 0.0747 μM (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.