Haematein as a reagent for thorium, zirconium and uranium

Summary Haematein gives violet colored complexes with thorium and uranium and an orange colored complex with zirconium of the stoichiometric ratios 16, 13, and 11 respectively of the metal and the reagent (Job's method). The reagent and the complexes of thorium, uranium and zirconium show absorption maxima at 520–540 m, 520–540 m 500–520 m respectively. In observations at 540 m in 60 percent aqueous acetone 0.05 mg of thoria (a 12 fold excess of cerite earths has no influence), 0.029 mg U₃O₈ and 0.025 mg of zirconia may be determined. The spectral characteristics of the complexes indicate a similarity in character in spite of differences in stoichiometric composition.