A novel and simple approach to element fractionation analysis: Single step fractionation of milk

A novel single step fractionation of cow's milk was achieved using ethyl ether, n-hexane and isopropyl alcohol (3:3:4) mixture via solubility difference and precipitation. Milks were separated into lipid, serum and protein fractions. The distribution of elements was determined by ICP OES and validated by the analysis of NIST-1549a. The applicability of the scheme was tested by the analysis of whole, skimmed, semi-skimmed and infant formula. The distribution tendency of each element was variable. The lipid and protein bound element concentrations ranged from 0.053 to 5.3 mg L-1 and 0.046-1111.2 mg L-1, respectively, whereas it was between 0.064 and 954.5 mg L-1 for the serum fraction. The trend of element distributions were in the order: protein > serum > lipid for the most elements, except for Mg, Na and K. This study provide practical and innovative way to elucidate the distribution of elements which may provide information to be applied in health and nutrition strategies.

Automated summary

A novel single step fractionation method was used to separate cow's milk into lipid, serum, and protein fractions using ethyl ether, n-hexane and isopropyl alcohol mixture. The distribution of elements varied among the fractions, with most elements having a higher concentration in the protein fraction compared to the serum and lipid fractions.