STUDY OF THE ABSORPTION-SPECTRA OF 4F ELECTRON TRANSITIONS OF THE NEODYMIUM COMPLEX WITH 8-HYDROXYQUINOLINE AND OCTYLPHENOL POLY(ETHYLENE GLYCOL)ETHER AND ITS ANALYTICAL APPLICATION

The absorption spectra of 4f electron transitions of the neodymium complex with 8-hydroxyquinoline and octylphenol poly(ethylene glycol)ether have been studied by conventional and third-derivative spectrophotometry. The absorption spectrum for neodymium at 575 nm is resolved into three bands centring at 572, 580 and 584 nm, respectively. The use of third-derivative spectra both eliminates the interference from other rare earth elements and enhances the sensitivity for neodymium. Beer's law is obeyed for 0-14 mug cm-3 of neodymium. The corresponding value of Sandell's sensitivity is 0.29 mug cm-2. The relative standard deviations evaluated from 11 independent determinations of 2.0 mug of neodymium are 0.87% for neodymium alone and 1.6% in the presence of 80 mug of lanthanum. The detection limit (signal-to-noise ratio = 2) is 0.12 mug cm-3 of neodymium. A method for the direct determination of neodymium in mixtures of rare earth elements with good accuracy and selectivity, is described.