A SPECTROPHOTOMETRIC DETERMINATION OF RHODIUM WITH TIN (II) BROMIDE

Abstract

Rhodium salts react with a solution of tin (II) bromide in hydrobromic acid to produce an intense yellow color suitable for a spectrophotometric determination of rhodium. The method described is relatively simple and is the most sensitive for this metal published to date. Several factors influencing the intensity and stability of the colored species, whose nature is unknown, are described. Since the other platinum metals and base metals interfere it is necessary to isolate the rhodium prior to its determination. However, a fair estimation of rhodium can be made even when equivalent quantities of iridium are present. The procedure may be adapted, with a small loss in sensitivity, to determine rhodium in solutions which have been fumed with sulphuric acid.