STUDY OF THE ABSORPTION-SPECTRA OF 4F ELECTRON TRANSITIONS OF THE NEODYMIUM AND ERBIUM COMPLEXES WITH DIPHACINONE AND TRITON X-100 AND ITS ANALYTICAL APPLICATION

The absorption spectra of 4f electron transitions of the neodymium and erbium complexes with 2-(diphenylacetyl)indan-1,3-dione and octylphen ol poly(ethyleneglycol)ether have been studied by normal and derivativ e spectrophotometry. Use of third-derivative spectra can eliminate the interference from other rare earth elements and enhance the sensitivi ty for neodymium and erbium. Beer's law is obeyed for 0-35 mug cm-3 of neodymium and 0-50 mug cm-3 of erbium. Their molar absorptivity at th e maximum absorption bands are about 7.4 times for neodymium and 11.4 times for erbium greater than that for the equivalent amount of neodym ium and erbium in the chlorides. The relative standard deviations eval uated from seven independent determinations of 8.3 mug cm-3 of neodymi um and 8.5 mug cm-3 of erbium are 1.4 and 1.5%, respectively. The dete ction limits (signal to noise ratio=2) are 0.06 mug cm-3 for neodymium and 0.1 mug cm-3 for erbium. A method for the direct determination of neodymium and erbium in mixtures of rare earth elements with good acc uracy and selectivity, is described.