Optimization of Sample Preparation Procedure for Determina-Tion of Fat-Soluble Vitamins in Milk and Infant Food by HPLC Technique

Abstract: Background: The analysis of vitamins in baby food is a challenging task given the com-plexity of the food matrix, vitamin stability, and strict regulations of the European Union regarding permissible deviations from declared values. Vitamins in food exist in different concentrations and forms and have different stabilities, and it is not straightforward to prepare samples for reliable analysis using the same procedure. Therefore, significant attention has been devoted to optimizing sample preparation in the analysis of vitamins. Methods: This study aims to determine which of the seven applied extraction methods is the most efficient for the simultaneous extraction and deter-mination of A, D, E, and K vitamins in milk and baby food using high-performance liquid chro-matography (HPLC). Different samples of baby food were prepared in seven different ways based on four methods (saponification, enzymatic hydrolysis, solvent extraction, and solid-phase extrac-tion). Results and Conclusion: The best preparation method proved to be solid-phase extraction with a C18 stationary phase, and HPLC with a UV-VIS detector was identified as a sufficiently sensitive technique for the identification and quantification of fat-soluble vitamins in milk and baby food.