Determination of Free Ethylenediaminetetraacetic Acid in Foods by Titration Using Eriochrome Black T with Visual End-Point Indication

Abstract

A direct titrimetric method for the determination of ethylenediaminetetraacetic acid (free EDTA) in foods is described. Free EDTA was extracted from food samples by equilibrium dialysis using ammonium buffer. An aliquot of dialyzate was subjected to direct titration with standard MgCl₂ solution at pH 8.5 using Eriochrome Black T as a metallochromic indicator. The common inorganic ions (PO₄³—, NO₃—, Cl—) and organic acids (citric acid, tartaric acid) in foods do not interfere with the proposed methods.