Extractive Spectrophotometric Determination of Samarium with Chlorophosphonazo III

Abstract

A rapid and sensitive extractive spectrophotometric method has been developed for the determination of samarium using 0.04% Chlorophosphonazo III in 1 mol · L^-1 hydrochloric acid media after extraction into isoamylalcohol. Absorbance was measured in 1-cm cell and the complex has a sensitive absorption peak at 667 nm. The complex of Sm(III)-Chlorophosphonazo III is formed instantly in organic phase and remains stable at least for 2 hours with constant absorbance under normal laboratory conditions. Validity of Beer’s law was verified in range 0 – 10 mg Sm(III) per 10 mL of the organic phase with an estimated molar absorptivity e₆₆₇ ~ 1.14 · 10⁵ mol^-1 · L¹ · cm^-1. Limit of detection (3-s approach) reached 0.22 mg Sm(III). The some foreign cations interference in samarium determination has been checked. The method
has been applied on spiked sample of mineral water. Obtained results of apparent recovery were found in very good agreement with acceptable range. The repeatability of this determination reached value not worse than ±5 % (n = 3).