Simultaneous Determination of Iron and Cobalt using Spectrophotometry after Catanionic Mixed Micellar Cloud Point Extraction Procedure

Abstract

A new preconcentration method which utilises a mixture of cationic and anionic surfactants for separation and spectrophotometric determination of iron and cobalt simultaneously has been developed. The metal ions, iron and cobalt were complexed with thiocyante. The hydrophobic complexes of iron and cobalt were then extracted into catanionic mixed micelles of cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulphate (SDS). Different parameters like concentration of HCl, concentration of thiocyanate, concentrations of the surfactants (CTAB and SDS), equilibration temperature and time were studied to get maximum efficiency. The linear ranges of Fe3+ and Co2+ were found to be 0.139 – 0.838 μg mL–1 and 5.89 – 35.4 μg mL–1, respectively the detection limits obtained were 1.54 ng mL–1 and 6.18 ng mL–1. The developed procedure has been employed for the retrieval of Fe3+ and Co2+ in water samples successfully (tap water and sea water). 98 – 107% recoveries were obtained.