Anodic Stripping Voltammetry Determination of Lead ions using Highly Sensitive Modified Electrodes Based on Multi-walled Carbon Nanotube

Two sensitive linear sweep and square wave anodic stripping voltammetry (LSand SW-) AdASV methods were optimized for trace determination of Pb+2 using carbon paste (CP) microelectrodes modified with mesoporous silica (SBA-15); mesoporous carbon (MC); and multi-walled carbon nanotube (MWCNT). Characterization of these modifiers were performed using XRD, TEM and BET. Lead (II) ion showed an anodic peak at -0.4 V in 0.1M HCl, using either bare or modified CP electrodes. A well-defined oxidation peak and high current response were observed using the MWCNT/CP electrode. Under optimal conditions (accumulation potential of -0.6 V for Ag/AgCl, and accumulation time of 15 min), a calibration curve ranging from 1x10-7 to 1x10-4 M was obtained for Pb+2 determination. A limit of detection (LOD) of 3×10-8 M Pb+2 was achieved using SW-AdASV at MWCNT/CP electrode. This (LOD) is much lower than that observed in most of the reported electrochemical methods. This method was successfully applied for trace determination of Pb+2 in various water samples without interferences from various organic and inorganic species. The results were statistically comparable to ICP-AES.