Abstract
Spectrophotometric determination of antimony has been conventionally made by extracting Rhodamine B-Sb (V) complex with benzene, after the excess of Ce(IV) added for the oxidation of antimony was destoryed with hydroxylamine hydrochloride. In the cases, however, the absorbance was widely variable and dependent upon the time of standing for the reduction of excess Ce(IV), and also decreased remarkably with the time of standing of extracted benzene solution.
A new modified method has been presented by the author to overcome these difficulties, whereby much higher reproducibility and stability of absorbance were obtained by the addition of 3 drops of 0.61.5M sodium nitrite solution as oxidizing agent instead of Ce(IV), and 0.5 ml of 1 : 2 butyl cellosolve solution per 25 ml of the sample solution of more than 4N in hydrochloric acid.
In this method, the removal of excess sodium nitrite was unnecessary, and the determination of antimony was done with high sensitivity.
