University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Website: @unf

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Inorganic compound

Classification: Inorganic compound -> lanthanum oxide

Citations 1

"Determination Of Traces Of Calcium And Magnesium In Rare-earth Oxides By Flow Injection Analysis"
Anal. Chim. Acta 1994 Volume 295, Issue 1-2 Pages 151-157
Duong Thanh Thuy, Dini Decnop-Weever, Win Th. Kok*, Pham Luan and Tu Vong Nghi

Abstract: Rare-earth oxides were dissolved in 15% HCl, the acid was evaporated off and the residue was dissolved in 10 mM HCl. The resulting solution was injected into a 10 mM HCl carrier solution and transported to a column (8 cm x 4 mm i.d.) packed with Chelex 100 resin (50-100 mesh, H+ form). The eluate merged with 7.5 µM-calcein solution in 0.2 M KOH in a PTFE mixing coil (20 cm x 1 mm i.d.). Fluorescence was measured at 515 nm (excitation at 300 nm) and the sum of Ca(II) and Mg(II) was determined. For the determination of Ca(II) alone, the column eluate was mixed with 5 mM 8-quinolinol in 10 mM KOH and for the determination of Mg(II) alone, the masking solution was 0.5 mM EGTA in 10 mM KOH. All flow rates were 1 ml/min. Calibration graphs for both cations were sigmoid for 1-20 µM with a linear portion at 2-12 µM. The method was applied to the analysis of La2O3, Pr2O3, Nd2O3, Sm2O3 and Gd2O3. The results of four synthetic samples agreed well with those predicted for the single metals; the sum was underestimated if the Mg(II) concentration was high. Two samples of La2O3 were also analyzed, giving results in fair agreement with those obtained by ICP-AES.
Calcium(2+) Magnesium(II) Sample preparation Fluorescence Method comparison Chelex