Extractive titration of iron (III) with cupferron using tiron as an indicator

Abstract

An extractive titration of iron(III) was attemped with a standard aqueous solution of cupferron as a titrant and tiron as an indicator. Chloroform was used as the extractant of iron(III) cupferrate. The titration was carried out at pH 3 of the initial aqueous solution, and only two or three rejections of the lower organic layer after each one minute's standing were sufficient for the satisfactory result. The standard cupferron solution was prepared by dissolving the reagent in water and standardized against a known amount of iron(III). By this method, 27μg/ml or more of iron could be determined. The effects of diverse metallic ions by the application of this method for rock salt, hydrochloric acid, potassium fertilizers and limestone, were examined.