Sulfite (SO32-) and thiosulfate (S2O32-) ions are used as food preservative and antichlor agent respectively. To detect low levels of such anions we used Cu(II) complex of the Tris-Methyl Pyridine Amine (TMPA) ligand, denoted L. Formation of [LCu(SO3)] (1) and [LCu(S2O3)] (2) in solution were monitored using UV-Vis, EPR and cyclic voltammetry, while the solid-state X-ray structures of both complexes were solved. In addition, we also evaluated the pH range in which the complexes are stable, and the anions binding affinity values for the [LCu(solvent)]2+ (3) parent complex. As a matter of illustration, we determined the sulfite content in a commercial crystal sugar.
Keywords: Copper(II); EPR; Sulfite; TMPA; Thiosulfate; UV–Vis.
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