Determination of Uranium in Thirty‐six Geological Reference Samples by Fluorimetry and Extractive Spectrophotometry

The uranium contents of 36 geological reference samples have been determined by fluorimetry after ion‐exchange separation, and spectrophotometry using Arsenazo III after solvent extraction with tri‐n‐octylphosphine oxide. The agreement between present results and published data is generally good. The methods of fluorimetry and spectrophotometry proved very convenient in the determination of uranium in geological materials.