SnO2/Reduced Graphene Oxide Nanocomposite for the Simultaneous Electrochemical Detection of Cadmium(II), Lead(II), Copper(II), and Mercury(II): An Interesting Favorable Mutual Interference

A well-known gas sensing material SnO2 in combination with reduced graphene oxide was used in heavy metal ions detection for the first time. This work reports the detailed study on the SnO2/reduced graphene oxide nanocomposite modified glass carbon electrode, which could be used for the simultaneous and selective electrochemical detection of ultratrace Cd(II), Pb(II), Cu(II), and Hg(II) in drinking water. The SnO2/reduced graphene oxide nanocomposite electrode was characterized voltammetrically using redox couples (Fe(CN)(6)(3-/4-)), complemented with electrochemical impedance spectroscopy (EIS). Square wave anodic stripping voltammetry (SWASV) has been used for the detection of Cd(II), Pb(II), Cu(II), and Hg(II). The detection limit (3 sigma method) of the SnO2/reduced graphene oxide nanocomposite modified GCE toward Pb(II), Cu(II) and Hg(II) is 1.015 x 10(-10) M, 1.839 x 10(-10) m M, 2.269 x 10(-10) M, and 2.789 x 10(-10) M, respectively, which is very well below the guideline value given by the World Health Organization. The chemical and electrochemical parameters that exert influence on deposition and stripping of metal ions, such as supporting electrolytes, pH value, deposition potential, and deposition time, were carefully studied. An interesting phenomenon of mutual interference was observed. Most importantly, we pose a potential for the use of gas sensing material in heavy metal ions detection.