Development of a Cyclic Voltammetric Method for the Determination of Cobalt(II) Ions Using o‐Nitrosophenol

The demand for cobalt-based alloys has been steadily increasing due to advancements in industrial and cutting-edge technologies, particularly in metallurgy, where cobalt plays a crucial role in high-performance superalloys, battery production, and corrosion-resistant materials. Consequently, the concentration of cobalt ions in wastewater and environmental samples has exceeded permissible levels, raising significant ecological concerns. This study presents the development of an efficient method for the determination of cobalt(II) ions using a silver/mercury film working electrode (Hg(Ag)FE) modified with the organic dye <i>ortho-nitrosophenol</i> (o-NF) through cyclic voltammetry (CV). Optimization of the experimental conditions revealed that an acetate buffer (0.1 M, pH 5.1) served as the supporting electrolyte, with an accumulation time of 10 s and a concentration of 2.0 μM o-nitrosophenol. The preconcentration conditions were adjusted to enhance the sensitivity and selectivity for cobalt(II) ion detection. The method exhibited a linear relationship in the concentration range of 0.040-0.160 μM (<i>R</i> ² = 0.9863), with a limit of detection (LOD) of 0.010 μM and a limit of quantification (LOQ) of 0.034 μM for Co(II) ions. The proposed method was successfully applied to the analysis of water samples from the Aydar-Arnasoy Reservoir, and the accuracy of the results was statistically validated using Student's <i>t</i>-test. These findings demonstrate the potential of the developed method as an effective tool for environmental monitoring and the determination of cobalt ions in ecological protection initiatives.