Separation and Preconcentration of Cobalt(II) from Water Samples with Amberlite CG-120 Resin

A selective solid-phase extraction method has been developed for the preconcentration and separation of trace amounts of Co(II). The method was based on the adsorption of Co(II) ions on the Amberlite CG-120 resin. The adsorbed Co(II) ions on the resin were eluted by 4 mol/L HCI and then they were determined by Flame Atomic Absorption Spectrometry (FAAS). Various experimental conditions, such as pH, type and concentration of eluent, the flow rate of sample and eluent solution, amount of resin, and sample volume were investigated to obtain better sensitivity and effective separation of trace levels of the Co(II) ions. Moreover, the interference effects of some ions on the recovery of Co(II) were also investigated. The developed method was applied for the determination of Co(II) ions in drinking and wastewater samples. The enhancement factor (EF) and limit of detection (LOD) values were found to be 25-fold and 9.32 µg/L, respectively. The accuracy of the method was tested by the certified reference material of TMDA-70.2 Lake Ontario Water and there was a good agreement between found and certified values at a 95% confidence level.