The quantitative spectrographic analysis of the rare earth elements

Abstract : Spectrographic methods applicable to the determination of major rare earth constituents in complex mixtures are described. The specific examples discussed are the determination of yttrium and gadolinium in the concentration range of 10 to 100 per cent. The procedures involve the high current DC arc excitation of rare earth oxide sample-ceric oxide-graphite mixtures. Selected lines of cerium are used as internal standards. The choice of cerium as internal standard was based on the relative ease with which any cerium, if present in a mixture, could be preferentially separated from the mixture, and then reintroduced in a standard amount. Precision studies show a standard deviation of about + or - 2.5 per cent of the amount present. Data are included which indicate that the high precision is attributable to excellent internal standard control of excitation variables. jg p.2