Polarographic study of cobalt(II) and manganese(II) at a dropping mercury electrode using 2-amino-3-hydroxypyridine as a complexing agent

Abstract

The polarographic behaviour of cobalt(II) and manganese(II) has been studied using 2-amino-3-hydroxypyridine as a complexing agent at a constant ionic strength, µ, of 0.6 M NaClO₄ and at pH 6.0 ± 0.5. Well defined diffusion-controlled irreversible waves were obtained for both metals. The forward rate constant (k⁰_f,h) and the charge-transfer coefficient (αn) were calculated. The diffusion current constants were 3.83 for cobalt and 3.16 for manganese, and were constant over the concentration ranges 0.50–6.00 and 0.50–8.50 mM, respectively. Based on the large difference in their half-wave potentials, a method is proposed for the simultaneous determination of these metals when they occur together in pure solutions. The method was applied to the determination of these metals in a number of standard alloys.