Analytical Approaches for the Identification and Quantification of Key Non-Protein Nitrogen Components in Infant Formula

This article provides a thorough review of various analytical methods utilized for the identification and quantification of non-protein nitrogen (NPN) components in infant formula (IF), specifically focusing on key NPN components such as urea, nucleotides, and free amino acids. Quantifying these components is essential for ensuring the nutritional quality of IF. The review evaluates the sensitivity, specificity, and applicability of different analytical techniques when applied to a complex matrix (i.e., IF), highlighting the advantages and limitations inherent in each approach. Although numerous methods exist for quantifying the different NPN components, not all are rigorously validated. Additionally, many methods fail to adequately account for matrix effects, which can lead to significant discrepancies in reported values. This review underscores the importance of selecting validated analytical approaches that consider matrix effects to obtain reliable data on NPN components in IF. By enhancing the understanding of NPN quantification in infant nutrition, this work aims to highlight the importance of standardized and validated analytical protocols, thereby improving consistency in the identification and quantification of key NPN components in IF.