Determining Sialic Acid Content and Variation
Sialic Acid Release and Labeling Kit (Ludger) and Monosaccharide Release and Labeling Kit (Ludger) were used to analyze the sialic acid and galactose contents, respectively. The detailed information was described in the Experimental section in the Supporting Information. UPLC analysis was performed within 24 min of sample preparation on an Agilent 1290 Infinity II System equipped with a fluorescence detector (excitation = 373 nm, emission = 448 nm). A 5 µL sample was injected onto a LudgerSep uR2 column (LS-UR2-2.1×100 for sialic acid, LS-UR2-2.1×50 for galactose). Each sample was applied after equilibrating the column with acetonitrile:methanol:water (9:7:84%) at 0.25 mL/min (for sialic acid) or BPT solvent at 30°C.