An indirect amplification procedure for the determination of niobium by atomic-absorption spectroscopy

Abstract

Niobium in the range 5 to 50 µg is determined by an amplification procedure in which molybdoniobophosphoric acid is formed and extracted into butanol. The molybdophosphoric acid, which is also formed, is first selectively extracted away from the molybdoniobophosphoric acid into isobutyl acetate. The eleven molybdate ions associated with each niobium atom are determined by direct atomic-absorption spectroscopy in a nitrous oxide-acetylene flame at 313·2 nm. Of the twenty-eight other ions studied, only titanium causes appreciable interference, although its presence at the same concentration as niobium can be tolerated. Large amounts of tantalum do not interfere.