An Improved Method of the Colorimetric Determination of Chromium with Diphenylcarbazide

Abstract

The colorimetric method of determining chromium in silicate rocks with diphenylcarbazide has the defect resulting in a distinct tendency for producing slightly lower figures as recognized already. After a thorough study of the method the author pointed out the possible sources for the serious errors, especially for those which give negative results. Thus the oxidation method in an alkaline medium was proposed, which was compared with the widely used old method. The accuracy and reproducibility of this method are not entirely satisfactory but so far it will serve as the most accurate method. The content of chromium in brown coal in Japan determined by this oxidation method with sodium peroxide will be reported in a later communication.