Fluorimetric determination of zirconium with 3-(2-carboxyphenyl)-1-methyltriazene N-oxide

Zirconium forms an intensely fluorescent stable metal chelate with 3-(2-carboxyphenyl)-1-methyltriazene N-oxide (λex(max) 378 and λem(max) 510 nm) in aqueous ethanolic solution under acidic condition. Based on this reaction, a method has been devised for trace determination of zirconium. The method is simple, rapid, sensitive and selective and has been successfully applied to analyse a number of synthetic mixtures containing Zr. The fluorescing system attains the maximum intensity after 30 min of standing and it remains almost unaltered even after 24 hr. Beer's law is obeyed from 25 ppb to 1.5 ppm of the metal. Over 35 cations and anions have been found to have no adverse effect on the determination of zirconium. Only, niobium, EDTA and oxalate give negative interference. (author)