Solvent extraction-spectrophotometric determination of boron in steel with 2,4-dinitronaphthalene-1,8-diol and Brilliant Green

Abstract

On the basis of previous work, a solvent extraction procedure has been applied to the determination of boron in steel. The boron (as boric acid) is converted to the monovalent complex anion, BR₂^–(where H₂R is 2,4-dinitronaphthalene-1,8-diol), in acetic acid medium, extracted as a coloured ion associate with Brilliant Green into toluene and determined spectrophotometrically. Steel samples were dissolved in a mixture of dilute hydrochloric acid and hydrogen peroxide and large amounts of iron and other metal ions in the solution were removed either by solvent extraction with 4-methylpentan-2-one or by precipitation as hydroxides or oxinates. Micro amounts of boron in steel samples (0.0013–0.012%) were determined.