Abstract:
A polyaniline/Zinc oxide (PANI/ZnO) nanocomposites based electrochemical sensor was
Prepared by electropolymerization of ananiline monomer on a Zinc oxide film modified
glassy carbon electrode (ZnO/GCE) at different film thickness to form PANI/ZnO/GCE. The
electrochemical behaviour of the PANI film on bare and ZnO modified GCE was
characterized by cyclic voltametry(CV) in monomer free 1.0 M HCl(aq) and EIS. CV of PANI
on bare and ZnO modified glassy carbon electrode revealed two anodic and cathodic peaks.
For comparison PANI and PANI/ZnO nanocomposites were also prepared chemically by
employing in-situ oxidation polymerization method and characterized by Uv vis, FT-IR, HRSEM
and HR-TEM. Similarily, chemically produced nanomaterials characterized
electrochemically showed two anodic and two cathodic peaks by CV in monomer
free 1.0 M HCl(aq). The PANI/ZnO/GC electrode was employed as sensor for the detection
of toxic heavy metal ions in water samples using Ostroyoung square wave anodic stripping
voltammetry (OSW ASV). The results indicated that the PANI-ZnO/GCE sensor was more
sensitive (with a dynamic linear range of 5.0 to 25.0 ppb and a detection limit (LOD) of 2.8,
1.84, 0.21 and 0.84 ppb for Cd(II), Pb(II), As(III) and Hg(II), respectively) than PANI/GCE
and/or GCE. PANI-ZnO/GCE as sensor exhibited lower detection limits than the WHO
permissible level of 5, 5, 10 and 5 µgL-1
for Cd(II), Pb(II), As(III) and Hg(II), respectively in
water. All the detections were performed under optimized experimental conditions.
