DETERMINATION OF Co(II) IONS BY INVERSION VOLTAMMETRY USING A MODIFIED GRAPHITE-BASED ELECTRODE
In this study, an inversion-voltammetric (IV) method for the determination of Co(II) ions was developed using a graphite-based
working electrode modified with diphenylcarbazone (DFK). Silver wire was used as the electrical conductor, ensuring high
conductivity. An acetate buffer solution with a pH of 4,4–4,6, a current of 2,5 µA, and an accumulation time of 90 s were selected
as the background electrolyte. The method demonstrated high sensitivity (R² = 0,998), accuracy, and reproducibility, with a linear
relationship for Co(II) ions in the concentration range of 1,0–50,0 µg/dm³ (detection limit 0,30 µg/dm³). Experiments with foreign
cations showed high selectivity, and the reliability of the method was confirmed by comparing results obtained with XRF and ICP
for cosmetic product samples. The proposed sensor is recommended as a promising and effective analytical approach for
monitoring Co(II) ions in cosmetic products.
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