A robust method using HPLC-UV was developed to improve the accuracy and repeatability of a quantitative method to detect 5 nucleotides (cytidine-monophosphate, uridine monophosphate, adenosine monophosphate, guanine monophosphate, and inosine monophosphate) in infant formulas. The results showed that efficient separation could not be achieved without strict conditions. The proposed method displayed a strong linear relationship (R2 > 0.9999) of single nucleotide in infant formula milk powder in the range of 10 to 1,000 mg/kg, a steady recovery (80.0% ∼110.0%) with relative standard deviation from 0.5% to 3.5%, under strict conditions of hydrophilic C18 column with di-isopropyl at 62.5 ± 2.5°C (± standard deviation), 0.65 ± 0.1 mg/mL tetrabutylammonium bisulfate, and mobile phase of pH of 2.75 ± 0.02. By applying this method on a series of milk products in the Chinese market, we found a few of them exceeded the legal limits of nucleotides.
Keywords: chromatographic conditions; high-performance liquid chromatography–ultraviolet; infant formula; nucleotide.
The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).