VOLUME 2 3, NO. 4, APRIL 195 1 589it was titrated while boiling against standard potassium permanganate solution.Both methods avoid the interference of chloride ion in the permanganate titration and gave identical results.This method was then used to investigate the conversion of aconitic acid to itaconic acid. In Figure 2 the results of experiments at various concentrations are reported, showing the determination with the bromine method and the new method. The regular and plausible course of the curve in the new method and the irregular course in the case of the bromine method are evidence of the usefulness of the proposed method.