Figure 1.

Overview of the capabilities of different strategies for the analysis of PSA and its sialylated glycopeptide linkage isomers. Six strategies typically used for PSA analysis are evaluated for their ability for absolute quantitation, throughput, robustness, glycoform profiling, and sialic acid linkage isomer-specific analysis. The gray figure indicates the capability per strategy. IA, immunoassay; TD-MS, top-down mass spectrometry; RP-MS, reversed-phase LC–MS; PGC-MS, porous graphitized carbon LC–MS; CE–MS, capillary electrophoresis coupled to MS; HILIC–MS, hydrophilic interaction liquid chromatography coupled to MS.