Spectrophotometric Determination of Lanthanum (III) and Some Rare Earths with Xylenol Orange

Authors: Primo A

DOI: 10.23880/macij-16000196

Volume 8, Issue 2

Abstract

Xylenol orange reagent was used to complex lanthanum cations in aqueous solutions, where the solution was colourless before complexing, and when adding Xylenol orange, it turned violet at a wavelength of 578 μm at a pH of about 6, where it was adjusted using a buffer solution composed of acetic acid and sodium acetate. Between the lanthanum cation and the indicator in a ratio of 1:1, the resulting complex is very stable for a time of up to 180 minutes at a room temperature of approximately 25 °C. Sulphate ions, chlorides and nitrates did not affect the absorbance of the solution at different concentrations, while fluorides, oxalates and tartrate negatively affected in high quantities, and the presence of EDTA and NTA negatively affects complex formation and stability.

Keywords: Xylenol Orange; Lanthanum Complexing Spectrophotometric Titrations

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