An improved method for the determination of manganese in rocks, minerals, ores, soils, steel, alloys, sea-bed polymetallic nodules and environmental samples including water and effluents

Geo-analytical Chemistry Laboratory, Regional Centre for Exploration and Research, Atomic Minerals Directorate, Department of Atomic Energy, Jamshedpur-831 002, Jharkhand, India

E-mail : ptarafder@sify.com

A highly useful and reliable extraction spectrophotometric method has been developed for the determination of manganese in a wide variety of samples having complex matrices based upon reaction system of Mn(II)-2,3- dihydroxynaphthalene, an O-O' type of ligand forming an anionic complex with manganese, irrespective of its valence states, which is readily extractable as a· purple ion-pair complex into methyl-isobutyl ketone (MIBK) under the influence of a cationic surfactant, cetyltrimethylammonium bromide (CTAB). The only interference of iron has been successfully eliminated by its prior extraction with methyl-isobutyl ketone (MIBK). The method is robust as is evidenced by its application to a wide variety of samples of diverse matrices, including certified reference materials. While most spectrophotometric methods, including formaldoxime, pyridil-azo-napthol and the well known permanganate method fail when applied to samples of complex matrices, developed method by us yields highly accurate results as attested by those obtained from AAS as well as by certified/recommended values CRMs.