Elimination of the spectral interference from polyatomic ions with rare earth elements in inductively coupled plasma mass spectrometry by combining algebraic correction with chromatographic separation

A simple and effective procedure is developed to avoid the spectral interference from light rare earth elements (REEs) and barium polyatomic ions on some rare earth elements in inductively coupled plasma mass spectrometry (ICP-MS) by combining algebraic correction with AG50W-x8 cation exchangeable chromatography. Algebraic correction is made to reduce the spectroscopic overlap interference of (PrO)-Pr-141-O-16 and (NdO)-Nd-143-O-16 on Gd-157 and Tb-159. The spectroscopic overlap interference of BaO+ and BaOH+ on some middle REEs are overcome by separation of REEs from barium with AG50W-x 8 cation exchangeable chromatography. Prior to the determination, REEs are separated from complicated matrix samples using AG50W-x 8 cation exchangeable resin. Ba is eluted with 2 mol/l HNO3 solution. REEs are retained and could then be eluted with 5 mol/l HNO3 solution. Recoveries for REEs are from 96 to 110%. More than 99.5% of Ba in the sample is removed,ensuring that the spectral interference from barium polyatomic ions on some middle REEs such as Nd, Sm, Eu and Gd are eliminated. The potential of the proposed method is evaluated by analysis of Certified Reference Materials (CRMs). Results show that experimental data are in good agreement with the certified values. The new technique has been successfully employed for the determination of REEs in practical soil and plant Samples. (C) 2001 Elsevier Science B.V. All rights reserved.