Estimation of the Optimum Concentration Interval of the Contents of Praseodymium, Neodymium, Europium, Holmium, and Erbium in a Solution

Abstract

Based on the electronic absorption spectra of Pr3+, Nd3+, Eu3+, Ho3+, and Er3+ ions in 1 M aqueous solutions of chloric acid, calibration graphs have been constructed in a “concentration of metals–optical density of a solution” format for different frequencies. The band for praseodymium was used at 22,520 cm−1, for neodymium at 17,380, 13,480, and 12,560 cm−1, for europium at 25,380 cm−1, for holmium at 18,580 and 15,580 cm−1, and for erbium at 39,160, 26,480, and 19,160 cm−1. The errors in determining the concentration of the indicated elements as a function of their content have been calculated. It is shown that for perchloric solutions of praseodymium it is possible to correctly determine its contents within the concentration range 0.1–1.5% at a frequency of 22,520 cm−1; for neodymium the ranges are 0.4−1.0, 0.3–1.0, and 0.5–1.0% at 17,380, 13,480, and 12,560 cm–1, respectively; for europium 0.4–1.5% at 25,380 cm−1; for holmium — 0.2–1.5 and 0.4–1.5% at 15,580 and 18,580 cm−1, and for erbium the range is 0.4–1.0% at frequencies of 39,160, 26,480, and 19,160 cm−1.