A disposable expanded graphite paper electrode with self-doped sulfonated polyaniline/antimony for stripping voltammetric determination of trace Cd and Pb

Abstract

A conducting graphite electrode was fabricated by using expanded graphite (EG) paper by a screen-printing technique, onto which self-doped sulfonated polyaniline (SPAN) was electropolymerized via aniline and m-aminobenzenesulfonic acid monomers, and the Sb/SPAN/EG electrode was obtained by electrodepositing Sb onto the copolymer modified EG electrode. The sensitivity of the disposable EG electrode was improved by using a two-step ex situ fabrication procedure, in which the anodic doping of SbCl₄⁻ for the SPAN film was kept at +0.3 V for 300 s and then reduced at −0.5 V for 100 s in solution containing 10 mg L⁻¹ Sb(III) and 0.5 M hydrochloric acid. The disposable Sb/SPAN/EG electrodes were used for the simultaneous determination of trace lead and cadmium by differential pulse anodic stripping voltammetry. The stripping currents increased linearly when the metal concentration was in a range of 2–70 μg L⁻¹, and the limits of detection were 0.20 μg L⁻¹ for Pb(II) and 0.41 μg L⁻¹ for Cd(II) at a preconcentration time of 180 s, respectively. The proposed disposable working electrode, as a new style of “mercury-free” electrodes for heavy metal measurements, exhibits encouraging properties for practical use, such as low cost, and good reproducibility.