Voltammetric and Polarographic Studies of Eriochrome Black T - Nickel(II) Complex

EBT is a carcinogenic azo-compound. It is well known that EBT has chelating properties. Therefore, EBT has been widely used for the determination of calcium, magnesium, manganese, zinc, zirconium, nickel, copper, thulium and cobalt1−5. Literature surveys have shown that extensive polarographic, spectroscopic and colorimetric studies on some metal complexes with EBT have been carried out4−13. The review of the literature indicates that the compositions and the electrochemical behaviour of the Ni(II)-EBT complexes has not been studied systematically so far1−16. No one has described the stability constants and the decomposition of the Ni(II)-EBT complexes. Therefore, the purpose of the present paper was to determine the stability constants and the composition of the Ni(II)-EBT complexes, using the polarographic and voltammetric techniques, in order to obtain detailed information on the interaction of the metal ion and the ligand. Voltammetry (especially SWV) is a very suitable technique because of its high selectivity and sensitivity and shorter analysing time. Also, the importance of this study comes from the application of EBT as a dye stuff and metal indicator. ∗To whom correspondence should be addressed