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 x 10(5) 1.mole(-1) .cm(-1). Beer's law is obeyed for 0.25-1.50 mug of zirconium in 25 ml of solution. The method has been used in the determination of zirconium in aluminium alloy and steel samples.