Total metal content and chemical speciation analysis of iron, copper, zinc and iodine in human breast milk using high-performance liquid chromatography separation and inductively coupled plasma mass spectrometry detection.

• Fe, Cu, Zn and I analyzed in breast milk of pre-term and full-term births. • Colostrum, transitional and mature milk show differences in Fe, Cu and Zn. • Speciation of Fe, Cu and Zn show association to biomolecules (proteins). • Micronutrient speciation analysis provide a superior understanding of breastfeeding. The aim of this research was to quantify essential trace elements (iron, copper, zinc and iodine) and establish their speciation in human milk. Both the element and the species are important in new-born nutrition. Colostrum, and transitional and mature milks (25) were collected from 18 mothers of pre-term or full-term infants. Concentrations of the target elements were determined using ICP-MS. For speciation, HPLC coupled to ICP-MS was employed. Total contents of the micronutrients varied in mothers of pre-term (Fe = 0.997, Cu = 0.506, Zn = 4.15 and I = 0.458 mg L−1) and mothers of full-term (Fe = 0.733, Cu = 0.234, Zn = 2.91 and I = 0.255 mg L−1) infants. Fe, Cu and Zn were associated with biomolecules with high molecular mass compounds, such as immunoglobulins, albumin and lactoferrin whilst iodine was only found as iodide. [ABSTRACT FROM AUTHOR]