Spectrophotometric study and analytical applications of lanthanide-kojic acid complexes Direct determination of Nd, Ho and Er in mixtures of rare earths

The complexes of the rare-earth metals with kojic acid in weakly alkaline solution are reported. The characteristic absorbances of neodymium, holmium and erbium can be increased by factors of 4.3, 11.0 and 6.4 respectively, compared with those of the chlorides. The third-derivative spectra have been used to eliminate the interference of Ce, La and Y, and the sensitivities are again increased, by a factor of 6-9.