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

Abstract

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 µg cm^–3 of neodymium. The corresponding value of Sandell's sensitivity is 0.29 µg cm^–2. The relative standard deviations evaluated from 11 independent determinations of 2.0 µg of neodymium are 0.87% for neodymium alone and 1.6% in the presence of 80 µg of lanthanum. The detection limit (signal-to-noise ratio = 2) is 0.12 µg 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.