SOME ASPECTS OF MATRIX EFFECTS CAUSED BY SODIUM TETRABORATE IN THE ANALYSIS OF RARE-EARTH MINERALS WITH THE AID OF INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION-SPECTROSCOPY

When inductively coupled plasma atomic emission spectroscopy (ICP-AES) is applied to the analysis of rare earth (RE) minerals, it is necessary to use a flux, for instance Na2B4O7, for the decomposition of samples. Some aspects of the matrix effect caused by large amounts of Na2B4O7 in the analyte solutions are studied in this work. First, it is shown that this matrix effect is lowered by a factor of two when selecting the aerosol-carrier gas flow giving maximum net line intensity instead of the one giving a maximum intensity ratio of fine-to-background. It became evident during a second series of experiments that the high concentrations of Na2B4O7 lower the excitation temperature. They also cause quenching of metastable argon which certainly contributes to the observed matrix effect. © 1979.