Polarographic behaviour of zinc(II) and manganese(II) at a dropping-mercury electrode using δ-valerolactam as a complexing agent

Abstract

The polarographic behaviour of zinc(II) and manganese(II) has been studied using δ-valerolactam as a complexing agent at a constant ionic strength, µ= 0.1 M KNO₃, and pH 6.5. Well defined diffusion controlled irreversible waves were obtained for both the metals. The forward rate constant (k⁰_f,h) and the charge-transfer coefficient (αn) were calculated. The diffusion-current constants were 5.06 for zinc and 3.09 for manganese, and were constant over the concentration ranges 0.50–4.0 and 0.50–3.50 mM, respectively. Based on the large difference in their E_½ values, a method is suggested for the simultaneous determination of these metals when they are present together in pure solutions. The method has also been applied to the determination of the metals in certain standard alloys.