SPECIATION OF SE, FE AND ZN IN HUMAN-MILK WHEY - THE USE OF INSTRUMENTAL NEUTRON-ACTIVATION ANALYSIS (INAA) TO CORROBORATE ELEMENT PROFILES MEASURED WITH INDUCTIVELY-COUPLED PLASMA-ATOMIC EMISSION-SPECTROMETRY (ICP-AES)

In human milk trace elements normally exist in a form which can easily be absorbed by the newborn infant. For investigations of the bioavailability of trace elements it is necessary to carry out a speciation analysis of the elements of interest. An independent analytical method has been used for the quality control of the shape of the element profiles obtained from the speciation analysis of Se, Fe and Zn in individual samples of human milk whey after chromatographic separation. For the element detection in the untreated milk fractions Instrumental Neutron Activation Analysis (INAA) was chosen as the reference method. Element distribution patterns have been obtained with Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) using on-line digestion of the fraction, reduction and hydride formation of Se (''T''-mode). Prior results are compared with those obtained by means of element detection in the untreated fractions (''U''-mode) with ICP-AES. The elution profiles of Se, Fe and Zn in human milk whey obtained by means of ICP-AES detection using the ''T''-mode show good agreement with the distribution patterns obtained with INAA. Recoveries of 103% for Fe, 86% for Zn and 87% for Se were obtained. The element distribution patterns of Fe and Zn obtained with ICP-AES speciation using the ''T''-mode also show good agreement with those obtained by means of ICP-AES using the ''U''-mode.