SENSITIVE SPECTROPHOTOMETRIC DETERMINATION OF ZIRCONIUM WITH P-ACETYLCHLOROPHOSPHONAZO IN THE PRESENCE OF SODIUM DODECYLBENZENESULFONATE

A sensitive spectrophotometric method for the determination. of zirconium was studied, with use of p-acetyl-chlorophosphonazo (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 mu g ml(-1) of zirconium. The molar absorptivity is 6.03 x 10(5) 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.