Determination of nucleotides and nucleosides in milks and pediatric formulas: a review

Nucleotides and nucleosides play important roles as structural units in nucleic acids, as coenzymes in biochemical pathways, and as sources of chemical energy. Milk contains a complex mixture of nucleotides, nucleosides, and nucleobases, and because of the reported differences in their relative levels in bovine and human milks, pediatric formulas are increasingly supplemented with nucleotides. Liquid chromatography is the dominant analytical technique used for the quantitation of nucleospecies and is commonly applied using either ion-exchange, reversed-phase, or ion-pair reversed-phase modes. Robust methods that incorporate minimal sample preparation and rapid chromatographic separations have been developed for routine product compliance analysis. This review summarizes the analytical techniques used to date in the analysis of nucleospecies in bovine and human milks and infant formulas.