Solid Phase Exteraction of cobalt (II) using Octadecyl Silica Membrane Disks Modified Nano-Fe3O4-Encapsulated-Dioctylphthalate and Linked-Diethylenetriamine

A novel and selective method for the fast determination of trace amounts of cobalt (II) in water samples has been developed. The procedure is based on the selective formation of Cd(II) using octadecyl-bonded silica membrane disks modified by nano-Fe3O4-encapsulated-dioctylphthalate and linked-diethylenetriamine (magnetic nano- Fe3O4 -DOP- DTA)at different pH in the presence of acetate as an enhancement agent of Co(II) signals followed by elution with organic eluents and determination by atomic absorption spectrometry. The maximum capacity of the employed disks was found to be 385 ± 5 µg for Co(II). The detection limit of the proposed method is 6.0 ng.L-1 for Co(II). The effect of potential interfering ions, ligand amount, stripping solvent, and sample flow rate were also investigated. Under the optimal experimental conditions, the break-through volume was found to about 1000mL providing a preconcentration factor of 500. The proposed method was successfully applied for determination ofCo(II) in different water samples.

Keywords: Co2+; Extraction; Octadecylslica disks; atomic absorption spectrometry; magnetic nanoFe3O4 -DOP- DTA.