Determination of Sialic Acid in Milk and Products Using High Performance Anion-Exchange Chromatography Coupled with Pulsed Amperometric Detection

A resolved succinct environmental-friendly chromatography method was developed for determination of N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc) in bovine milk and products using high performance anion-exchange chromatography coupled with pulsed amperometric detection. The conditions affecting separation, detection, and sialic acid release from milk were optimized. The separation was finished on CarboPac PA20 anion-exchange column using 100 mM NaOH and 20–300 mM NaAc elution in 20 min at a flow rate of 0.5 ml min−1. The separation and detection temperatures were both at 30°C. The detection was carried out on gold working electrode. The detection limits (25 μl injection, three times of the baseline noise) were 3.0 and 1.8 μg l−1, and the linear range of 5–500 μg l−1 was obtained. The spiked recovery of Neu5Ac and Neu5Gc in real samples was 88%–115%.