Sensitive spectrophotometric determination of zirconium with p-acetylchlorophosphonazo in the presence of sodium dodecylbenzenesulfonate

Abstract

A sensitive spectrophotometric method for the determination of zirconium was studied, with use of p-acetylchlorophosphonazo (CPApA) as reagent. Zirconium reacts very sensitively with CPApA in the presence of sodium dodecylbenzenesulfonate (SDBS) to form a blue complex. The zirconium complex exhibits maximum absorption, in 0.8–2.8 mol l^–1 hydrochloric acid medium, at 419 nm. Beer's law is obeyed over the range 0–0.12 µg ml^–1 of zirconium. The molar absorptivity is 6.03 × 10⁵ l mol^–1 cm^–1 at 419 nm. The molar ratio of zirconium to CPApA in the complex is calculated to be 1:4 in the presence of SDBS. The method has been satisfactorily applied to the determination of zirconium in its alloys with aluminium, copper and magnesium.