DETERMINATION OF ULTRATRACE NEODYMIUM IN HIGH-PURITY LANTHANUM COMPOUNDS BY HIGH-ACCURACY ISOTOPE-DILUTION INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRIC ANALYSIS WITH CHEMICAL PRECONCENTRATION

Direct, accurate quantitation of ultratrace Nd in La compounds was not possible by ICPMS. The La/Nd ratio of > 10(6) required chemical separations to provide a suitable sample solution for instrumental analysis. Separation of Nd from the La matrix is problematic since the two elements are close in mass and similar in chemical behavior. The ICPMS in a semiquantitative survey mode proved to be a valuable tool in developing the required separations. Nd was quantified using isotope dilution which requires neither 100% recovery nor absolute isolation of the Nd, resulting in considerable flexibility in the design of preconcentration procedures. Nanogram per gram quantities of Nd in high-purity La compounds were determined using this procedure.