An automatic, modified formaldoxime method for determining low concentrations of manganese in water containing iron

Abstract

An automatic method for determining manganese in fresh water with the AutoAnalyzer is described, together with details of the analytical system. The method is based on a modification of the formaldoxime procedure published by Goto, Komatsu and Furukawa,¹ which consists in reacting manganese with formaldoxime in alkaline solution, and decomposing any iron formaldoxime formed with EDTA and hydroxylammonium chloride.

Aluminium, zinc, copper, iron, calcium, magnesium, chloride and phosphate do not interfere at concentrations above those normally found in natural water in Norway.

The capacity of the method is 25 samples per hour, and the standard deviation is 5 µg of manganese per litre.

A statistical comparison of the manual persulphate oxidation method with the automatic formaldoxime method indicated that both methods give identical results.