Study of kinetics of complexation reaction of Co with 2-benzoylpyridine-4-phenyl-3-thiosemicarbazone and kinetic-spectrophotometric determination of cobalt

Kinetics of the complexation reaction of Co²⁺ with 2-benzoylpyridine-4-phenyl-3-thiosemicarbazone (BPPT) was spectrophotometrically examined at 421 nm. The ligand that was developed for a simple kinetic-spectrophotometric determination of Co²⁺ was based on 1:2 complex formation between Co²⁺ and BPPT. The complexation reaction was carried out in ethanol-water medium at 25 °C. Kinetic and activation parameters of the complexation reaction were calculated, and the rate equation and the reaction mechanism were proposed. The calibration graph is linear in the concentration range of 0.10−2.91 mg·L⁻¹ for the tangent method. The species that caused interference were investigated.