▎ 摘　　要

This work proposes the conventional sonochemical synthesis of nanoparticles of tin (IV) oxide on reduced graphene oxide (rGOS@SnO2) influencing the formation of a composite with enhanced properties. The combination of SnO2 nanoparticles with rGOS weakens the accumulation in layered structures of the latter system, which leads to better exposure of SnO2 active sites and thus increases the conductivity of rGOS@SnO2 composite. This validates the improved electro-catalytic activity of the composite based on previous reports for its successful utilization in the electrochemical determination of toxic contaminants. The quantitative determination of mercury ions, through the use of the electrochemical sensor based on rGOS@SnO2 manifests several advantages such as simple operator, promptness, cost effectiveness and time independency when compared to other traditional techniques. The fabricated sensor displays two wide linear responses in the range of 0.25-705.3 mu M for mercury ions, with a rapid response time about 1 s, and with a high sensitivity of 10.18 mu A mu M-1 cm(-2) under optimized conditions. The accumulation of traces of mercury in the bodies of fish in the marine eco system marks the significance of its detection in real samples. The satisfactory results of the proposed sensor establish the supreme efficacy of layered nanomaterials in conjunction with nanoparticles for the simple, rapid and efficient detection of pollutants in food and biological samples. (C) 2020 Elsevier B.V. All rights reserved.