Determination of Stability Constants of Cadmium(II) Complexes with Diallyl Disulfide, Dimethyl Disulfide and Diallyl Sulfide Using Differential Pulse Voltammetry

Abstract

The study of the binding of heavy metal ions by organosulfur compounds of garlic is especially important for the understanding of many biological systems. Cadmium is a non-essential heavy metal known to be one of the most toxic environmental pollutant.Interactions between cadmium and diallyl disulfide (DADS), dimethyl disulfide (DMDS) and diallyl sulfide (DAS) were investigated by differential pulse voltammtery. Determination of the stability constants of cadmium(II) with DADS, DMDS and DAS complexes was based on the DeFord–Hume methodology that calculated from the dependence of the shift of cadmium( II) peak potential upon addition of the ligands DADS, DMDA and DAS separately. The results of this study provide evidence of the formation of 1: 1 and 1: 2 complexes between cadmium(II) and DADS, DMDS and DAS with stability constants (β) in the range of ca. 10^5.8–10^6.2 and 10^9.6–10^10.6 respectively.