State of the art in sample preparation for human breast milk metabolomics-merits and limitations

Human breast milk (HBM) contains metabolites that are diverse in chemical structure and concentration. These metabolites range from high-abundance to low-abundance compounds and from polar to nonpolar. This complex nature of HBM makes HBM samples difficult to analyze, especially in global metabolomic studies for the determination and characterization of complete sets of metabolites. In this review, the state of the art in sample preparation for HBM metabolomics is presented, as this approach for HBM metabolite analysis has received increased attention. The methods used for endo- and exogenous metabolites extraction from the HBM matrix are summarized and characterized. The merits and limitations of these methods are discussed. The challenges associated with the preparation of HBM samples for metabolomic analysis are also indicated. (C) 2019 Elsevier B.V. All rights reserved.