Silver nanoparticles decorated carboxylate functionalized SiO₂, New nanocomposites for non-enzymatic detection of glucose and hydrogen peroxide

Highlights: • Silver nanoparticles decorated carboxylates functionalized SiO₂ were prepared. • Ligands are bonding to silica support as SiO₂–pro–NH₂ and SiO₂–pro–NH–cyanuric–NH₂. • These nanomaterials were used as electrochemical sensors for H₂O₂ and glucose detection. • H₂O₂ and glucose could be detected as low as 0.094 and 0.33 μmol L⁻¹, respectively. - Abstract: Here, two different nanocomposites are prepared based on the decoration of silver nanoparticles (AgNPs) on carboxylated SiO₂. SiO₂ was functionalized with two different carboxylate ligands to stabilize silver nanoparticles on them, using two different organic bondings. Then, AgNPs were decorated successfully on the surface of the functionalized SiO₂. The functionalized SiO₂ and AgNPs-functionalized SiO₂ were characterized using Fourier transform infrared spectroscopy, elemental analyses, and Transmission electron microscopy (TEM). For further characterization, the generated nanoparticles were employed as modifiers in the preparation of carbon paste electrodes (CPEs). Then, cyclic voltammetry and electrochemical impedance spectroscopy were used to study their electrochemical behavior. The electrochemical data exhibited that the modifications of CPE led to easier electron transfers rather than the bare and unmodified SiO₂/CPE due to the presence of functionalized SiO₂ in accompany with electrocatalytic effects of the decorated silver nanoparticles. Furthermore, the modified–CPEs were examined as non–enzymatic H₂O₂ and glucose sensors using electrochemical techniques including cyclic voltammetry and hydrodynamic chronoamperometric. Electrochemical results represented that the modified-CPE is efficient and sensitive for H₂O₂ and glucose detection as low as 0.094 and 0.33 μmol L⁻¹, respectively. At last, the practical applications of these sensors were also evaluated by analyzing H₂O₂ and glucose in the presence of common interfering species in real samples such as human blood plasma and ultra–high–temperature (UHT) dairy products.