Gold nanoparticles embedded in silica sol–gel matrix as an amperometric sensor for hydrogen peroxide

Gold nanoparticles (Aunp) embedded in methyltrimethoxysilane sol–gel (SG) film coated electrode was prepared (GC/SG-Aunp) and characterized. The electrochemical response observed for the GC/SG-Aunp electrode reveals that the dispersed gold nanoparticles in the silicate film are in electrical contact with each other. The potassium ferricyanide redox couple was used as a marker to probe the tunable kinetic barrier of the gold nanoparticles dispersion in the silicate matrix. The GC/SG-Aunp electrode showed good electrocatalytic response for hydrogen peroxide (H2O2) reduction without an enzyme or mediator immobilized in the silicate sol–gel film. Linear relationship was observed for H2O2 reduction in the concentration range from 2.5 to 45 μM at the GC/SG-Aunp electrode at an applied potential of −0.5 V and the detection limit was calculated as 3.15 nM. The GC/SG-Aunp modified electrode is simple to prepare and this electrode shows fast response, good stability and reproducible results and could be applied as an amperometric sensor for H2O2.