2-AA labeled glycans (2-aminobenzoic acid) are considered to be a superior standard for glycan analysis due to the higher sensitivity of detection as compared to 2-AB labeled glycans. Labeled glycans may be analyzed by high-sensitivity fluorescence detection or monitoring of UV-absorbance during various chromatographic and structure sequence analyses, as well as mass spectrometry. UHPLC, HPLC, ESI-MS, MALDI-MS and CE methods have been developed and are commonly used in the analysis of therapeutic glycoproteins such as EPO and antibody-based bio-therapeutics. Methods include ion exchange, normal phase, reverse phase, and size exclusion chromatography.
The 2-AA labeled glycans are supplied as 100 pmols dried form from an aqueous solution. They are stable at least 5 years as supplied and after reconstitution. Typically the 2-AA labeled glycans are reconstitute with 100 µls of the buffer solution being used, yielding a concentration of 1 pmol/µl. It is recommended to dissolve the dried glycans in the aqueous solution first (ammonium formate). 35ul + 65ul ACN will make 100 pmol in 100ul concentration.