Elimination of interference from aluminium in the determination of total iron in soils and plant materials using 1,10-phenanthroline reagent

Aluminium, in solution, enhances the iron-1,10-phenanthroline colour, leading to high results in the determination of iron. Both the iron and aluminium complexes of phenanthroline exhibit identical absorption characteristics. Attempts to mask the aluminium in solution with sodium fluoride have been unsuccessful as the fluoride ions suppress the colour formed with iron and the reagent. The determination of iron after the separation of aluminium and phosphates is simple and rapid. The method presented is reliable and recoveries are quantitative.