A facile electrochemical sensor designed from gold nanoparticles embedded in three-dimensional sol-gel network for concurrent detection of toxic chemicals

Abstract

An electrochemical sensor was prepared using gold nanoparticles (Au_nps) embedded in (3-aminopropyl)triethoxysilane (APS) derived silicate sol-gel three-dimensional network (APS-Au_nps). The APS-Au_nps modified electrode was found to efficiently electrocatalyze the oxidations of N₂H₄, SO₃^2-and NO₂^- in the absence of any other electron transfer mediators/enzyme immobilized in the APS-Au_nps modified electrode. The electrooxidation peaks appeared at 0.05, 0.2 and 0.55 V for N₂H₄, SO₃^2- and NO₂^- in pH 7.2 at the APS-Aunps modified glassy carbon electrode (GC/APS-Au_nps) with a large decrease in the over potentials to the extent of ~750 mV, ~600 mV and ~250 mV, respectively. The electrochemical sensors designed using the APS-Aunps modified electrode was also used for the concurrent detection of N₂H₄, SO₃^2-and NO₂^- in a mixture. The electrochemical sensor prepared using APS-Au_nps modified electrode was very stable and highly sensitive, and showed fast response.