Determination of Selenium in Human Milk by Hydride Cold-Trapping Atomic Absorption Spectrometry and Calculation of Daily Selenium Intake

A technique of hydride cold-trapping atomic absorption spectrometry following microwave digestion was developed and optimized for the determination of selenium in human milk. The method was validated by the analysis of two standard reference materials (CRM milk powder). The detection limit was 0.5 ng mL-1. The method was then used to analyze 78 milk samples from 38 Austrian mothers throughout their first 10 months of lactation. The mean concentration of selenium in the mother's milk decreased with the days postpartum from 23.9 ± 12.0 μg L-1 in colostrum to a plateau of 11.4 ± 3.0 μg L-1 in mature milk. On the basis of the milk selenium concentrations, the selenium intakes of the fully breast-fed infants and the lactating mothers were calculated. The selenium intake of the infants during their first 3 months of life was >8.2 μg day-1. The selenium intake of the lactating mothers was 48 μg day-1. Compared to the recommended dietary allowance, the fully breast-fed infants received sufficient selenium but the lactating mothers obtained less than the recommended. Keywords: Selenium; human milk; daily intake; mothers; infants; Austria; microwave digestion; hydride generation atomic absorption spectrometry