The colorimetric determination of pyrogallol with sodium metavanadate in an acetone-water solution

Abstract

In the determination of pyrogallol with sodium metavanadate, a shallow S-shaped absorption curve was obtained from which two separate linear calibration graphs were established, one for the determination of the lower pyrogallol concentrations (equivalent to 0·1 to 0·3 mg of pyrogallol), the other for the higher concentrations (equivalent to 0·45 to 0·8 mg). The effect of the initial volume, time required, volume of water, metavanadate concentration and the stability of the pyrogallol have been studied. The method was also applied to some other polyhydroxyphenolic compounds for purposes of comparison. Also, the precision and the accuracy of the proposed method are compared with those obtained by the A.O.A.C. method.