Micellar-Enhanced Highly Sensitive Reaction of Rare Earths with Xylenol Orange and Surfactants. Study of Reaction Conditions and Optimization of Spectrophotometric Method

Abstract

Reaction conditions in rare earths(RE)-Xylenol Orange(XO)-cationic surfactant ternary system were studied in detail. Conditional molar absorptivities up to 150000 mmol⁻¹ cm² were reached. Highly sensitive spectrophotometric method for 15 RE elements (REE) was evaluated under optimal conditions of 0.06 mmol dm⁻³ XO, 0.6 mmol dm⁻³ cetylpyridinium bromide, and 0.01 mol dm⁻³ acetate buffer of pH 4.50. Calibration plots measured at 600, 610, and 620 nm were linear up to 5.5 μmol dm⁻³ REE. The best detection limits of 0.04–0.20 jimol dm⁻³ REE were reached at 610 nm. In comparison with the previous results, the sensitivity of determination was increased and the range of knowledge of the mentioned ternary system was extended.