Differential Pulse Anodic Stripping Voltammetry Determination of Lead(II) and Cadmium(II) with Multiwalled Carbon Nanotubes-Thiol Functionalized Chitosan Modified Bismuth Film Electrode

摘要

A sensitive electrochemical method for simultaneous determination of lead and cadmium was developed using multiwalled carbon nanotubes-thiol functionalized chitosan (MWCNTs-CS-SH) modified glassy carbon electrode in 0.1 mol L~(-1) acetate buffer with pH 4. The thiol functionalized chitosan was prepared by covalent tethering with cysteamine using glutaraldehyde, then reduced by sodium borohydrate. The anodic oxidation of Pb(II) and Cd(II) produced two well-defined and separated stripping peaks at about -0.58 V for Pb(II) and -0.82 V for Cd(II), respectively. Linear responses were obtained in the range from 4 to 20 mg L~(-1), with a limit of detection of 0.4 μg L~(-1) for both metal ions under optimized conditions. Several important operational parameters influencing the electroanalytical stripping response of MWCNTs-CS-SH modified electrode were optimized, such as me concentration of Bi(III) ions, deposition potential, deposition time and pH value of the acetate buffer. The influences of emulsifiers to the stripping analysis were also investigated.