Sensitive stripping voltammetry detection of Pb(II) at a glassy carbon electrode modified with an amino-functionalized attapulgite

Abstract

The electroanalysis of Pb2+ ions using an organoclay modified electrode is reported herein. The amine functionalized attapulgite used as electrode modifier was prepared by the covalent grafting of [3-(2-Aminoethylamino)propyl]trimethoxysilane (AEPTMS). The properties of the obtained hybrid material were studied by various physico-chemical techniques, including infrared spectroscopy, X-ray diffraction and CHN elemental analysis that together confirmed the effectiveness of the grafting process. The modified clay was then coated as thin film onto the active surface of a glassy carbon electrode (GCE) and the resulting modified electrode was evaluated for the electrochemical determination of Pb2+. A two-step analytical procedure was used: the accumulation at open circuit of Pb2+ and its detection by anodic stripping differential pulse voltammetry. Various experimental parameters that can influence i-E curves of Pb2+ at the GCE modified electrode were fully investigated and optimized. A linear response for Pb2+ was obtained in the concentration range from 4×10−12M to 4×10−11M, with a detection limit estimated at 0.88×10−12M (S/N=3). The interfering effect of some ions likely to influence the stripping determination of Pb2+ was evaluated and the proposed method was successfully applied to the analysis of laboratory tap water.