Determination of manganese(II) by a photoactivated, catalytic method

Abstract

A method is described for the determination of Mn^II based on the photoactivated oxidation of sulphite using the specific photosensitizer Rose Bengal. The reactivity of Mn^II is approximately ten times higher for the photosensitized, acetylacetone-activated reaction than for the system that is only chemically activated. The determination of Mn^II is not interfered with by a large excess of Co^II, Cu^II, Ni^II, Cr^III, Cd^II or Fe^III. The detection limit of the proposed method is 0.3 ppb with a relative standard deviation of about 5.5%. A proposal for a possible reaction mechanism is made on the basis of spectrophotometric measurements. The catalytic method described was used for the determination of Mn^II in drinking water.