Sample Preparation for HPLC Determination of Free and Oligosaccharides-Bound Sialic Acid in Bovine Colostrum

An analytical method was developed for determining free and oligosaccharide-bound sialic acids in bovine colostrum by HPLC. The condition of acid hydrolysis for sample and sialic acids derivatization were investigated. The sialic acids were released from their parent oligosaccharides by acid hydrolysis using 40mL 0.1mol/L sulphuric acid for 100min. They were then derivatized using O-phenylenediamine (OPD) at 70°C for 40 min, the determination of the derivative could be carried out by UV detection. The total content of free and oligosaccharide bound sialic acids in bovine colostrum milk were 941.95μg/mL. The developed method is validated on various dairy products such as bovine milk and milk-based products.