UV-Visible Spectrophotometric Method for Complexes Stoichiometry between Zn(II), Mg(II), Cd(II), Ca(II) and Cu(II) with Clonidine Hydrochloride

In the present study, an accurate, rapid, and simple, UV-Visible spectrophotometric method was developed for determining complexes stoichiometry of Zn(II)-clonidine hydrochloride, Mg(II)-clonidine hydrochloride, Cd(II)-clonidine hydrochloride, Ca(II)-clonidine hydrochloride, and Cu(II)-clonidine hydrochloride. The spectra of the complexes formed between clonidine hydrochloride with Zn (II), Mg (II), Cd (II), Ca (II), and Cu (II) cations were determined at 190-400 nm and the stoichiometry of the complexes formed between clonidine hydrochloride with the mentioned metal cations was determined at maximum wavelength using the mole ratio method. The stoichiometry of Cu²⁺-clonidine hydrochloride, Cd(II)-clonidine hydrochloride, Zn(II)-clonidine hydrochloride, and Mg(II)-clonidine hydrochloride were calculated as 1:1, but Ca(II)-clonidine hydrochloride, the complex was 1:2. The recovery was 100.8% for clonidine hydrochloride. The LOQ and LOD were 0.003 and 0.0028 µg/mL, respectively for clonidine hydrochloride. The interaction between clonidine hydrochloride with Cu²⁺, Ca^{2 +} Cd²⁺, Mg²⁺, and Zn²⁺ were evaluated using the UV-vis spectrophotometric method, and reasonable results were obtained.