• Svitlana V. Tymoshuk V. Tymoshuk Ivan Franko National University of Lviv
  • Orest S. Fedyshyn Ivan Franko National University of Lviv
  • Lesya O. Kobryn Stepan Gzhytskyi National University of Veterinary Medicine and Biotechnologies of Lviv
  • Ihor O. Patsay Ivan Franko National University of Lviv
  • Lesya V. Oleksiv Ivan Franko National University of Lviv
  • Oleksandr S. Tymoshuk Ivan Franko National University of Lviv http://orcid.org/0000-0001-9812-4850




The article is devoted to the study of the voltammetric activity of Co(II) in the presense of azo dyes with further using of the results obtained in analytical practice. The voltammetric behaviour of Со(II) complexes with eriochrome red B, eriochrome black T, kalces and 1-[(5-(3-nitrobenzyl)-1,3-thiazol-2-yl)diazenyl]naphthalen-2-ol was investigated using cyclic linear sweep voltammetry. The optimal conditions for complex formation were established. New peaks caused by the reduction of the Co(II)–azodye complex compounds are observed on the voltammograms. Sensitive and highly reproducible methods for cobalt determination were developed using the linear dependence of peaks height on metal concentration with limit of detection of 10-7 mol·L-1. The accuracy of the proposed method was assessed by the method of standard additions. The developed method was successfully applied for the determination of vitamin B12 in pharmaceutical formulations.


Author Biography

Oleksandr S. Tymoshuk, Ivan Franko National University of Lviv

доцент кафедри аналітичної хімії


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