Determination of trace amount of manganese by the use of square-wave polarograph

Studies on the polarographic analysis. XXXXI

Abstract

A series of supporting electrolytes was examined Table I Determination of Mn in Fe alumfor the determination of trace amount of manganese by the square-wave polarography, whereby triethanolamine in alkaline media was found the most adequate. From the result of fundamental experiments, the following procedure has been recommended : to a sample solution containing 1.122 μg of Mn is added triethanolamine and potassium hydraxide until their final concentrations in the electrolysis solntion reach 0.2M and 0.5M, respectively.
Air is passed through the solution heated in a boiling water-bath for about twenty minutes. The solution of manganese ions oxidized to +3 state produces a sharp reproducible wave at a peak potential of -0.5 volt vs. S. C. E. in the square-wave polarogram.
A linear relationship hold over the concentration range from 2×10^-5 to 1×10^-6M of manganese in the solution.
Only copper ion when present more than 1×10^-5M intereferes with the determination.
The present method was applied to the determination of a trace amaunt of manganese (of the arder af 0.005%) in reagent grade ferric alum and a satisfactory agreement was obtained with the value by the spectrophotometric method.