Thiol–ene chemistry guided preparation of thiolated polymeric nanocomposite for anodic stripping voltammetric analysis of Cd2+ and Pb2+

Abstract

We report on the thiol–ene chemistry guided preparation of a novel thiolated polymeric nanocomposite involving polyaniline (PANI), a functionalized thiol, e.g., sulfur-rich 2,5-dimercapto-1,3,4-thiadiazole (DMcT), and multiwalled carbon nanotubes (MWCNTs) for the sensitive differential pulse anodic stripping voltammetric determination of Cd²⁺ and Pb²⁺ on a glassy carbon electrode (GCE). Briefly, the thiol–ene reaction of a thiol with oxidized PANI that was chemically synthesized in the presence of solution-dispersed acidified MWCNTs yielded a thiolated polymeric nanocomposite of thiol-PANI/MWCNTs. The thiols examined include DMcT, 1,6-hexanedithiol and β-mercaptoethanol. Quartz crystal microbalance, cyclic voltammetry, scanning electron microscopy, Fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy were used for film characterization and process monitoring. Under the optimized conditions, the obtained Bi/Nafion/DMcT–PANI/MWCNTs/GCE can sensitively sense Cd²⁺ and Pb²⁺ with limits of detection of 0.01 and 0.04 μg L⁻¹, respectively.