Synthesis of new copper nanoparticle-decorated anchored type ligands: Applications as non-enzymatic electrochemical sensors for hydrogen peroxide

In this work, copper nanoparticles (CuNPs) decorated on two new anchored type ligands were utilized to prepare two electrochemical sensors. These ligands are made from bonding amine chains to silica support including SiO₂–pro–NH₂ (compound I) and SiO₂–pro–NH–cyanuric–NH₂ (compound II). The morphology of synthesized CuNPs was characterized by transmission electron microscopy (TEM). The nano-particles were in the range of 13–37 nm with the average size of 23 nm. These materials were used to modify carbon paste electrode. Different electrochemical techniques, including cyclic voltammetry, electrochemical impedance spectroscopy and hydrodynamic chronoamperometry, were used to study the sensor behavior. These electrochemical sensors were used as a model for non-enzymatic detection of hydrogen peroxide (H₂O₂). To evaluate the abilities of the modified electrodes for H₂O₂ detection, the electrochemical signals were compared in the absence and presence of H₂O₂. From them, two modified electrodes showed significant responses vs. H₂O₂ addition. The amperograms illustrated that the sensors were selective for H₂O₂ sensing with linear ranges of 5.14–1250 μmol L⁻¹ and 1.14–1120 μmol L⁻¹ with detection limits of 0.85 and 0.27 μmol L⁻¹ H₂O₂, sensitivities of 3545 and 11,293 μA mmol⁻¹ L and with response times less than 5 s for I/CPE and II/CPE, respectively. As further verification of the selected sensor, H₂O₂ contained in milk sample was analyzed and the obtained results were comparable with the ones from classical control titration method. - Highlights: • Copper nanoparticles decorating on two new anchored type ligands were prepared. • Ligands are bonding to silica support as SiO₂–pro–NH₂ and SiO₂–pro–NH–cyanuric–NH₂. • These materials were used as electrochemical sensors for H₂O₂ detection. • H₂O₂ could be detected as low as 0.27 μmol L⁻¹