Electrochemical Determination of Vitamin B12 (Cyanocobalamin) using Mercury Nanodroplets Supported at Montmorillonite on a Carbon Paste Electrode (CPE)

Abstract

A simple and effective electrochemical sensor for cobalt using mercury nanodroplets supported on montmorillonite (MMT) was developed. Physical analyses allowed the identification of crystalline structure, morphology, and presence of mercury structures in MMT-Hg²⁺ with nanometric dimensions between 3 and 11 nm. Electrochemical responses obtained by differential pulse anodic stripping voltammetry (DPASV) using carbon paste electrode modified with montmorillonite decorated with mercury nanodroplets (CPEM-MT-Hg) toward cobalt (II) provide a limit of detection (LOD) of 3.4 × 10⁻⁶mol L⁻¹, limit of quantification (LOQ) of 1.1 × 10⁻⁵mol L⁻¹, and a linear dynamic range (LDR) from 3.5 × 10⁻⁵ to 2.9 × 10⁻⁴mol L⁻¹. The developed method was applied to the determination of cobalt ions in a commercial vitamin B12 sample.

Keywords:

• Carbon paste electrode (CPE)
• differential pulse anodic stripping voltammetry (DPASV)
• mercury nanodroplets
• montmorillonite (MMT)
• vitamin B12 (cyanocobalamin)

Acknowledgements

We gratefully acknowledge the financial support by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) – Finance Code 001, 88887.517992/2020-00 and 88887.504861/2020-00. The authors also acknowledge the financial support by CNPq (grants 408309/2018-0; 311290/2020-5, 309803/2020-9 and 402195/2020-5) and Fundação Araucária (PBA2022011000056).

Author contributions

Lismery P. Souza: Conceptualization, Formal analysis, Investigation, Methodology, Validation. Alan R. F. Lima: Formal analysis, Visualization, Writing – original draft. Thomas A. C. Martins: Writing - Review & Editing. Fernando Campanhã Vicentini: Formal analysis, Visualization, Writing – original draft. Luiz Humberto Marcolino-Junior: Conceptualization, Resources, Funding acquisition, Writing – review & editing. Márcio F. Bergamini: Conceptualization, Resources, Funding acquisition, Supervision, Writing – review & editing.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that influenced the work reported in this paper.