Determination of carbohydrate heterogeneity in the humanised antibody CAMPATH 1H by liquid chromatography and matrix-assisted laser desorption ionisation mass spectrometry

The carbohydrate heterogeneity in a humanised immunoglobulin CAMPATH 1H has been evaluated by liquid chromatography (LC) and matrix-assisted laser desorption ionisation mass spectrometry (MALDI-MS). Derivatization of enzymically released carbohydrates with 1-phenyl-3-methyl-2-pyrazolin-5-one (PMP), a reagent previously deployed for monosaccharides, facilitated both LC and MALDI-MS analysis. The LC profile and MALDI-MS demonstrate twelve components. Owing to resolution limitations and potential component mass coincidences, respectively, neither method alone may fully reveal the true heterogeneity, which must be defined, before the numerous glycoforms can be identified.