Inorganic analysis in organic solvents: Spectrophotometric determination of chromium following a chromatographic separation

A new method is described for the determination of chromium. In a suitable solution, trivalent chromium is precipitated as its 8-hydroxyquinolate, or 8-hydroxyquinaldate, in the presence of trivalent iron. The dried precipitate is dissolved in chloroform, and the solution, diluted once with benzene, is passed through an activated alumina Chromatographic column. The optical density of the eluate, containing the chromium complex only, is measured at 410 or 425 mμ with respect to the solvent. Aluminium, vanadium and cobalt interfere when 8-hydroxyquinoline is used as reagent; but when 8-hydroxyquinaldine is used, the method is unequivocal.