Determination of nucleotides in infant milk formulas using novel dendrimer ion-exchangers

The main aim of the present study was to develop a method for the separation of 5′-monophosphate nucleotides with the use of ion chromatography. Novel dendrimeric stationary phases were used for this purpose. The effects exerted by the type of anion-exchanger support (silica or polymeric) and the number of stationary phase layers on nucleotide retention were studied. A silica-based dendrimeric anion-exchanger was most suitable for analyzing the studied compounds. An increase in the number of layers enhanced nucleotide retention inside the column. The separation efficiency of the studied compounds was tested at various concentrations of the mobile phase buffer. At higher phosphate buffer concentrations, nucleotide resolutions were achieved in 6 min. Three commercially available infant milk formulas were analyzed to verify the applicability of the studied method. Solid phase extraction was used for sample cleanup and concentration. The limit of quantification of nucleotides was 0.40 μg/ml, and the method was linear in the concentration range of 0.40–20.6 μg ml−1.