Electrochemical and spectral studies of rhodanine in view of heavy metals determination

Abstract

The electrochemical study of 2-Sulfanylidene-1,3-thiazolidin-4-one (rhodanine, R) was performed on a glassy carbon working electrode by using three methods: differential pulse voltammetry (DPV), cyclic voltammetry (CV), and linear sweep voltammetry (LSV) at rotating disk electrode voltammetry (RDE). The CV, DPV, and LSV at RDE curves for R were recorded at different concentrations in 0.1 M TBAP/CH₃CN. Polymeric films were formed by successive cycling at different potentials and by controlled potential electrolysis. The film formation was proved by recording the CV curves of the chemically modified electrodes (CMEs) in transfer solutions containing ferrocene in 0.1 M TBAP/CH₃CN. The obtained CMEs were used for the detection of heavy metal ions. Synthetic samples of heavy metal ions (Cd (II), Pb (II), Cu (II), Hg (II)) of concentrations between 10⁻⁷ and 10⁻⁵ M were analyzed using CMEs prepared in different conditions. The most intense signal was obtained for Pb(II) ion (estimated detection limit = 10⁻⁷ M), which shows that these CMEs can be used for Pb(II) ion detection. The ability of R to form complexes with Pb(II) ion was also tested by UV-Vis spectrometry. The obtained results showed the formation of Pb(II)R₂ as the most stable complex.