Preconcentrative separation of erbium from Y, Dy, Ho, Tb and Tm by using ion imprinted polymer particles via solid phase extraction

Erbium(III) ion imprinted polymer particles were synthesized by preparing ternary complex of erbium imprint ion with 5,7-dichloroquinoline-8-ol (DCQ) and 4-vinylpyridine (VP) and then thermally copolymerizing with methyl methacrylate (functional monomer) and ethylene glycol dimethacrylate (cross linking monomer) in the presence of 2-methoxy ethanol (porogen) and 2,2'-azobisisobutyronitrile (initiator). The imprint ion was removed by stirring the above particles with 50% (v/v) HCl to obtain leached IIP particles. Control polymer (CP) particles were similarly prepared without imprint ion. CP and unleached and leached IIP particles were characterized by spectral, thermal, microanalysis and nitrogen adsorption studies. The preconcentration and selectivity studies for erbium and other selected lanthanides were carried out with leached CP and HP particles. The preconcentration of 2.0-250 mug of erbium(III) present in 250 ml of solution was possible with as low as 50 mg of IIP particles in the pH range 7.3-7.8. Seven replicate determinations of 25 mug of erbium(III) present in 250 ml of solution gave a mean absorbance of 0.148 with a relative standard deviation of 2.5%. The detection limit corresponding to three times the standard deviation of the blank was found to be 2 mug/250 ml. (C) 2004 Elsevier B.V. All rights reserved.