Determination of Phytic Acid in Various Foods by Indirect Photometric Ion Chromatography

Abstract

An indirect photometric ion chromatographic method (PIC) using a conventional high performance liquid chromatograph system equipped with a UV detector was established for the determination of phytic acid (PA) in foods. PA could be determined on an anion exchange column, Shim-pack IC-A1 (Shimadzu), with 0.3 mM naphthalene-l,3,6-trisulfonic acid tri-sodium salt (NTS) adjusted to pH 5.5 as the eluent. The eluate was monitored at 295 nm. The sample, which had been extracted with 0.6N hydrogen chloride and neutralized with 0.1 A sodium hydroxide, was applied to an anion exchange resin column (AG1-X4). PA fraction eluted with 2N hydrogen chloride was evaporated to dryness and dissolved in water. After filtration through a membrane (pore size; 0.45 μm), 5-50μl of the filtrate was subjected to PIC. The recovery of PA from soybean, barley or wheat flour was in the range from 93.0 to 98.3%. The determination limit was 0.05 g/kg. The highest PA content, 72.4-87.0 g/kg, was observed with rice brans among various foods examined. © 1988, Japanese Society for Food Hygiene and Safety. All rights reserved.