IMPROVED DETERMINATION OF PHYTATE BY ION-EXCHANGE CHROMATOGRAPHY

An improved method for the ion chromatographic determination of phytic acid is presented. The method is based on a recently published chromatographic method combined with a treatment of the samples with EDTA. Separation and quantitation of phytic acid were performed on an anion-exchange column. Phytic acid was detected at 300 nm after reaction with a ferric salt in an in-line postcolumn derivatization. The improved method described here was compared with a recently published HPLC method without EDTA treatment and with a method using small single-use ion-exchange columns. It was found that the HPLC method without EDTA treatment of the samples results in values too low for phytic acid, whereas the method using small single-use ion-exchange columns gives values too high. The differences between the results of the three methods were statistically significant (p < 0.01).