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 electrophoret ic 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 hydrochlori c acid, 0.0056 mol/L bis-tris-propane (pH.6.1) as leading electrolyte, and 0.005 mol/L 2-morpholinoethanesuIfonic acid as terminating electr olyte is most appropriate for the analysis-of phytic acid in real samp les using a volume-coupling isotachophoretic instrument. Calibration w as 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 corre sponds to a phytic acid content of the samples of less than 0.08%. The precision of the determinations including sample pretreatment, expres sed by the relative standard deviation, was 3.8%.