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.