DETERMINATION OF PHYTIC ACID IN CEREAL-GRAINS, LEGUMES, AND FEEDS BY CAPILLARY ISOTACHOPHORESIS

A method is described for the determination of phytic acid in various plant materials and feeds based on isotachophoresis. The electrophoretic migration properties of phytic acid, the lower inositol phosphates, and phosphate were investigated in various buffering systems. It was found that the electrolyte system consisting of 0.01 mol/L hydrochloric acid, 0.0056 mol/L bis-tris-propane (pH.6.1) as leading electrolyte, and 0.005 mol/L 2-morpholinoethanesuIfonic acid as terminating electrolyte is most appropriate for the analysis-of phytic acid in real samples using a volume-coupling isotachophoretic instrument. Calibration was carried out in the concentration range between 10(-5) and 1.2 x 10(-4) mol/L. The detection limit was less than 10(-6) mol/L, which corresponds to a phytic acid content of the samples of less than 0.08%. The precision of the determinations including sample pretreatment, expressed by the relative standard deviation, was 3.8%.