title: Chromotropic acid azo dyes of the pyridine series Spectrophotometric determination of nickel and cobalt in the presence of many ions and their simultaneous determination.
abstract: Pyridyl-2-azo-chromotropic acid (disodium salt) is proposed as a new reagent for the determination of nickel and cobalt in the presence of many ions and for their simultaneous determination in the absence of cyanide and EDTA. The wavelengths of maximum absorption for the nickel and cobalt complexes are 570 and 640 mmu respectively. Beer's law is obeyed by the complex systems from 0.125-0.8 ppm of nickel and 0.16-1.2 ppm of cobalt. The optimum concentration ranges are 0.25-0.8 ppm for nickel and 0.16-1.2 ppm for cobalt and the relative error is 2.7 %. The molar absorptivities for the complexes of nickel and cobalt are 40,720 and 33,600, while the dissociation constants at pH 7.5 and 22 degrees are of the order of 10(-12) and 10(-13), respectively. The metal to reagent ratio is 1:3.
authors.affiliation: Department of Inorganic and Analytical Chemistry Jadavpur University, Calcutta-32, India.
authors.forename: A K
authors.initials: AK
authors.lastname: Majumdar
authors.forename: A B
authors.initials: AB
authors.lastname: Chatterjee