Thin-layer chromatographic detection of metal-EDTA complexes in human faeces

Abstract

The application of a thin-layer chromatographic technique combined with ion-exchange chromatography for the detection of metal-EDTA complexes in human faeces is described. Reproducible separations were obtained on silica gel and cellulose pre-coated plates using appropriate solvent systems. These complexes were easily identified from the specific colours produced after spraying with an appropriate reagent. Using this procedure, it was possible to detect some of these complexes when added to human faeces in amounts corresponding to approximately those which would be formed if a meal (containing the normal requirements for the metals) were fortified with the recommended maximum amount of Fe(III)-EDTA (10 mg of Fe as the complex). However, when the experiment was carried out in vivo, that is, the subjects ingested a meal together with the complex, or with Fe(III)-EDTA plus ten times the normal requirements of the metals as inorganic salts, none of the complexes was detected in the faeces in either instance.