Abstract
Manganese in iron, steel and iron ore was determined polarographically, by using a supporting electrolyte of 0.5M triethanolamine with 1M sodium hydroxide, whereby following facts were found. In the presence of chromium(III) in triethanolamine-sodium hydroxide solution, manganese(III) triethanolamine was decomposed and manganese was precipitated. This was prevented by preliminary oxidation of chromium(III) to chromium(VI). Addition of potassium cyanide to this supporting electrolyte had a profit of diminishing the copper wave, which appeared close to that of manganese(III) and interfered. However, potassium cyanide acted slowly on manganese(III) to reduce it, and an addition of its large amount lowered the reproducibility of manganese wave. This was avoided by the use of cyanide concentration less than ca. 0.02M.
