Sensitive spectrophotometric determination of traces of zirconium with 2-(6-bromo-2-benzothiazolylazo)-5-diethylaminophenol in the presence of sodium lauryl sulphate

A simple and highly sensitive procedure for spectrophotometric determination of zirconium has been developed. At pH 4.6, zirconium reacts with 2-(6-bromo-2-benzothiazolylazo)-5-diethylaminophenol in the presence of sodium lauryl sulphate to form a red-violet complex, which has an absorption maximum at 520 nm. The molar absorptivity at 520 nm is 4.4 × 10⁵ 1.mole⁻¹ .cm⁻¹. Beer's law is obeyed for 0.25–1.50 μg of zirconium in 25 ml of solution. The method has been used in the determination of zirconium in aluminium alloy and steel samples.