Abstract
Various examinations on the quality of phenylfluorone used in colorimetric analysis of tin or germanium were made. This paper deals with a method of purification of the reagents being sold in the market.
Comparative studies were made on the differences of appearences, linearity of the calibration curves in colorimetric analysis of tin, and of stability against time and light, etc., of seven samples of phenylfluorone, including the one synthesized in our laboratory.
It was found that the quality of phenylfluorone might be improved by removing impurities with hot ethanol extraction, and that the stabilities against time and light increased as the purity increased.
In the colorimetric analysis of tin or germanium, it will be recommendable to measure phenylfluorone at 470mμ with a molecular extinction coefficient of more than 4×104.
