Study of the absorption spectra of the 4f electron transition of the Nd and Er complexes with 2-isobutylformyl-1,3-dione-indane in the presence of TX-100 and its analytical application.

The absorption spectra of 4f electron transitions of the systems of neodymium and erbium with 2-isobutylformyl-1,3-dione-indane and TX-100 have been studied by normal and derivative spectrophotometry. Their molar absorptivities at the maximum absorption bands are about 7.2 (at 571 nm) times greater for neodymium and 13.1 (at 519 nm) times greater for erbium than those in the absence of the complexing agents. Use of second derivative spectra both eliminates the interference from other rare earths and increases the sensitivity from neodymium and erbium. Beer’s law is obeyed from 0∼20 μg/ml for neodymium and 0∼25 μg/ml for erbium. The relative standard deviations are 1.2% and 1.6% for 5.0 μg/ml of neodymium and 8.0 μg/ml of erbium, respectively. The detection limits (signal-to-noise ratio=2) are 0.14 μg/ml and 0.20 μg/ml. A method for the direct determination of neodymium and erbium in rare earth mixtures with good accuracy and selectivity is proposed.