Investigation of the Effect of Ph on the Optical Density of the Co(ii)–5-Chloro-8-Hydroxyquinoline Complex

This study investigates the formation conditions of the Co(II) ion complex with 5-chloro-8-hydroxyquinoline using a spectrophotometric method. The effect of solution pH on the optical density of the formed complex was examined, and the maximum absorption wavelength as well as the optimal complexation conditions were determined. The highest optical density was observed at λmax = 480 nm and pH = 5.0. The influence of buffer composition on the analytical signal was also evaluated, and the concentration range obeying the Beer–Lambert law was established. The obtained results demonstrate that the Co(II)–5-chloro-8-hydroxyquinoline complex is sufficiently stable and can be successfully applied for the spectrophotometric determination of cobalt in various analytical samples.