Solvent extraction separation of cobalt(II) with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC-88A)

Liquid-liquid extraction of cobalt(II) from 0.25 mol l(-1) ammonium acetate using 0.05 mol l(-1) 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester (PC-88A) dissolved in toluene has been proposed. The stable blue coloured c omplex formed by PC-88A with cobalt(II) was used for direct spectrophotomet ric determination at 630 nm. It obeys Beer's law in the range 10-140 mu g m l(-1). Effect of various parameters such as reagent concentration, equilibr ation period, effect of various diluents and foreign ions on percentage ext raction of cobalt were studied. This method was extended for the determinat ion of cobalt in real samples. The extraction reaction proceeds with cation exchange mechanism and the extracted species has the Co2Ac2L2. 2HL formula .