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 mu mol 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. (C) 2016 Elsevier Ltd. All rights reserved.