Determination of Rare Earth Elements by Solid Phase Extraction Using Chemically Modified Amberlite XAD-4 Resin and Inductively Coupled Plasma-Optical Emission Spectrometry

Abstract

A new solid phase extraction method was developed for the preconcentration and determination of the rare earth elements (REEs) Pr, Sm, Eu, Gd, Tb, Dy, Ho, Tm, Yb, and Lu at trace levels using a mini-column packed with 8-hydroxy-2-quinolinecarboxaldehyde functionalized Amberlite XAD-4 resin. The REE ions were adsorbed onto the resin and then eluted with 2 mL of 1.0 mol L-1 HNO3 solution and determined using inductively coupled plasma-optical emission spectrometry (ICP-OES). In order to achieve the best performance for the method, the effects of several parameters such as sample pH, sample and eluent flow rate, sample volume, and matrix ions on the method efficiency were investigated. Under the optimum conditions, detection limits between 0.010 and 0.420 mu g L-1 for a preconcentration factor of 12.5 were achieved. The sorption capacities for the resin were found to range between 49.6 mu mol g(-1) (for Yb) and 112.4 mu mol g(-1) (for Pr). In order to verify the accuracy of the developed method, a certified reference material (SPS-SW2 Batch 127 surface water) was analyzed, and the results obtained were in good agreement with the certified values. The method was also successfully applied to the determination of REEs in water samples with recoveries in the range of 88.4-100.5 % being obtained.