High performance liquid chromatographic determination of EDTA, calcium (II)-EDTA and iron (III)-EDTA in canned and bottled foods

A practical method was developed for the fractional determination of ethylenediaminetetraacetate (EDTA), Ca (II)-EDTA and Fe (III)-EDTA in canned and bottled foods. Bismuth (III) subnitrate suspended in sodium chloride-ammonium buffer solution was suitable for conversion of EDTA to the equivalent amount of Bi (III)-EDTA at pH 10, leaving Ca (II)- and Fe (III)-EDTA intact. Further, Ca (II)-EDTA was converted to Cu (II)-EDTA in the presence of Cu (II) ion at pH 2-3, leaving Bi (III)- and Fe (III)-EDTA unaltered. The resulting EDTA-chelates of Bi (III), Cu (II) and Fe (III) were separated by high performance liquid chromatography on a Nucleosil 5C18 column using 2M ammonium sulfate solution as the eluent. The recoveries of EDTA, Ca (II)-EDTA and Fe (III)-EDTA were satisfactory. It was found that the addition of EDTA to foods caused the formation of Ca (II)-EDTA in all samples and that of Fe (III)-EDTA in several samples. Four imported food samples were analyzed by the proposed method. One sample, sandwich spread, contained 29.2μg/g of Ca (II)-EDTA and 11.0μg/g of Fe (III)-EDTA.