Speciation of iron in breast milk and infant formulas whey by size exclusion chromatography-high performance liquid chromatography and electrothermalatomic absorption spectrometry

Speciation of iron in milk was carried out by high performance liquid chrom atography (HPLC) and electrothermal atomic absorption spectrometry (ETAAS). Milk whey was obtained and low molecular weight protein separation was per formed by size exclusion chromatography (SEC) with a TSK Gel SW glass guard (Waters) pre-column and a TSK-Gel G2000 glass (Toso Haas) column. After st udying water as a possible mobile phase, this mobile phase was carefully se lected in order to avoid alterations of the sample and to make subsequent i ron determination in the protein fractions easier by ETAAS, The proposed me thod is sensitive (limit of detection [LOD] and LOQ 1.4 and 4.7 mu g 1(-1) respectively) and precise (relative standard deviation [RSD] < 10%). Iron i s principally found in the proteins of 3 and 76 kDa in breast milk, and it is irregularly distributed in infant formulas. (C) 2000 Elsevier Science B. V. All rights reserved.