An electrochemical sensor was developed for the detection of nitrobenzene derivatives and nitrite ions using silver nanoparticles (Ag NPs) deposited on amine functionalized silica (SiO2).spheres modified electrode. The electrocatalytic reduction of nitrobenzene and oxidation of nitrite ions were studied using SiO2/Ag NPs at three different Ag concentrations (1, 2 and 3 mM) modified electrodes. In electrocatalysis, a positive shift in the reduction peak potential for nitrobenzene and a significant increase in the catalytic oxidation current for nitrite ions were observed at these modified electrodes. An improved electrocatalytic activity for the reduction of nitrobenzene and oxidation of nitrite ions was achieved at the SiO2/ Ag (3 mM) NPs modified electrode due to the large number of Ag NPs deposited on SiO2 surface. The lowest experimental detection limits of 500 nM for nitrobenzene derivatives and 1 AM for nitrite ions at the SiO2/Ag NPs modified electrode were observed. (C) 2014 Elsevier B.V. All rights reserved.