Used as a stable isotope-labeled internal standard in mass spectrometry for the quantification of sialic acid metabolism intermediates. Enables accurate tracking of metabolic flux in glycosylation pathways, particularly in studies of cellular glycoprotein synthesis and metabolic disorders. Commonly applied in pharmaceutical research and biomarker discovery where precise isotopic labeling is required to distinguish endogenous compounds from spiked standards. Also utilized in metabolic labeling experiments to monitor glycan biosynthesis in live cells with reduced metabolic perturbation.