Spectrographic analysis of solution for the rare earth by a glow discharge of Grimm lamp

Abstract

A glow discharge by Grimm lamp was applied to the spectrographic determination of Sc, Y and rare earth (R.E.) elements in acidic solution. Sample solution of 10μl was dropped onto the copper plate which had been polished with emery paper (AA# 240), and dried by a infra-red lamp. The glow discharge lamp was operated on the conditions of 3.7 Torr argon pressure and 1200 V discharge voltage. The discharge current was varied from 20 to 100 mA by the kind and concentration of acid. Emission light was focussed on the entrance slit (width 40 μm, height 1.8 mm) and exposed on the photographic plate, therefore spectral line intensity of anode center area (1 mmφ) of the glow discharge tube was determined. Spectral intensity ratio of Y to La versus acid concentration did not change for hydrochloric acid. Analytical line pairs YII 377.433 /LaII 379.477 and others were suitable for spectrographic determination of Y, and calibration curve for Y was linear in the range of (0.810)μg of Y. Repeatability for 2.04μg of Y was (4.0011.9) % (n=5) and minimal amounts of R. E. elements for detection were (0.115)μg. Usually R. E. chlorides are deliquescence, but OH band spectra were not detected. This technique might be applied to the chemical analysis of various elements in solution.