title: Solvent extraction-absorptiometric determination of niobium in steels with bromopyrogallol red.
abstract: A simple and rapid method is described for the determination of niobium in steel with Bromopyrogallol Red. After dissolution of the sample, niobium is extracted along with iron from concentrated hydrochloric acid into isopentyl acetate. Niobium and iron are stripped into an aqueous solution containing sodium acetate, and EDTA, ammonium chloride, tartaric acid, and Bromopyrogallol Red are added to complex the niobium. The niobium-Bromopyro-gallol Red complex along with excess of reagent is extracted into isopentyl acetate containing di-n-octylmethylamine, and measured at 610 nm. The molar absorptivity is 2.50 x 10(4) and Beer's law is obeyed up to 27 mug of niobium. The method is free from interferences and can be applied to the analysis of samples containing as little as 0.01 % niobium.
authors.affiliation: Chemistry Department, Imperial College, London S.W.7, U.K.
authors.forename: T V
authors.initials: TV
authors.lastname: Ramakrishna
authors.forename: S A
authors.initials: SA
authors.lastname: Rahim
authors.forename: T S
authors.initials: TS
authors.lastname: West