Simultaneous determination of metal ions. Catalytic oxidation of cobalt by metal ions when extracted with quinolin-8-ol

The catalytic effect of various ions on the aerial oxidation of Co(II) when extracted from weakly acidic solutions with quinolin-8-ol in chlorofom was studied. Oxidation is complete only in the presence of Fe(III) or V(V). Mixtures of Al(III), Cu(II), Fe(III) and Ni(II) with Co(II) at concentrations in the range 1–8 μg ml^?1 were analysed by using a multi-component analysis program involving first-order derivative spectra. Because of the metal ion interaction, a multivariate calibration process is required. The recovery factors achieved ranged from 93 to 111%.