Catalytic method for the determination of trace amounts of manganese employing catalytic oxidation of fuchsin with oscillopolarographic detection

Abstract

A sensitive and selective catalytic method for the determination of manganese at levels as low at 0.2 ng ml −1 is described, based on the Mn(II)-catalysed redox reaction between fuchsin and KIO 4 in the presence of nitrilotriacetic acid as activator and in acetate buffer solution (pH 4.1). KCNS was used to quench the reaction, and single-sweep oscillopolarography was employed to measure fuchsin, which exhibits a sensitive wave at −0.78 V vs. SCE. Manganese in aluminium alloy and waste water samples was determined by the method, the results are in agreement with those of a spectrophotometric method using formaldoxime. The polarographic character of fuchsin and the catalytic reaction mechanism are discussed.