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 separ ations to provide a suitable sample solution for instrumental analysis . Separation of Nd from the La matrix is problematic since the two ele ments are close in mass and similar in chemical behavior. The ICPMS in a semiquantitative survey mode proved to be a valuable tool in develo ping the required separations. Nd was quantified using isotope dilutio n which requires neither 100% recovery nor absolute isolation of the N d, resulting in considerable flexibility in the design of preconcentra tion procedures. Nanogram per gram quantities of Nd in high-purity La compounds were determined using this procedure.