Sean Austin - Determination of sialic acids in milks and milk-based products

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      Publication Details (including relevant citation   information):

      Spichtig,V., Michaud,J., Austin,S. (2010) Analytical   Biochemistry 405: 28-40


      Sialic acids are becoming recognised as important components of   milk-based products for infants and young children. As such many   companies now label the sialic acid content of their products. In   order to control the labelling, suitable methods are required for   this analysis. The objective of this work was to set up a rapid   and sensitive method for the determination of the two most   commonly occurring sialic acids, N-acetylneuraminic acid (Neu5Ac)   and N-glycolylneuraminic acid (Neu5Gc), using high-performance   liquid chromatography (HPLC). The sialic acids were released from   their parent oligosaccharides, glycoproteins or glycolipids by   mild acid hydrolysis using formic acid. They were then   derivatised using 1,2-diamino-4,5-methylenedioxybenzene (DMB),   and subsequently separated on a Zorbax SB-Aq Rapid Resolution   column in less than 2 min. The method developed was validated on   various milk-based products and ingredients containing sialic   acid at levels from 0.3 to 900 mg/100 g.  Spiking   experiments indicate the sialic acid recoveries ranged from 87 –   108 %. The expanded measurement uncertainty was typically below   15% for Neu5Gc and typically below 10% for Neu5Ac or the sum of   the sialic acids, with a few exceptions. The proposed method is   fast, specific and easy to set up for compliance analysis in a   routine laboratory

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