Quantification of bovine milk oligosaccharides using liquid chromatography-selected reaction monitoring-mass spectrometry.

Oligosaccharides are important components of milk with bioefficacy as prebiotics, anti-infectives, and immune system modulators and as a possible source of sialic acid for neural function. Bovine milk oligosaccharides are lower in concentration and lack the diversity of human milk oligosaccharides but could be a commercial source of milk oligosaccharides for pediatric foods. For this development, an ability to quantify the oligosaccharides is required. This study validated a hydrophilic interaction chromatography high-performance liquid chromatography-high-resolution selected reaction monitoring-mass spectrometry (HILIC HPLC-HRSRM-MS) method for measuring six different oligosaccharides in bovine milk, bovine colostrum, and infant formulas. The extraction resulted in a high recovery (90-103%) with a repeatability coefficient of variation ranging from 2 to 9% for the two dominant oligosaccharides, 3'-sialyllactose and 6'-sialyllactose, and ranging from 1 to 17% for the much lower concentration oligosaccharides, 6'-sialyllactosamine, disialyllactose, and N-acetylgalactosaminyllactose. The sixth oligosaccharide, 3'-sialyllactosamine, was not detected in any of the samples.