Determination of amino sugars and amino acids in glycoconjugates using precolumn derivatization with o-phthalaldehyde

This report examines the RP-HPLC separation of o-phthalaldehyde derivatives of amino acids, amino sugars, and amino sugar alcohols using either 2-mercaptoethanol or 3-mercaptopropionic acid. A method with pmol sensitivity for the analysis of N-acetylamino sugars of glycoconjugates was elaborated. Upon hydrolysis, amino sugars are reduced with borohydride. Automated precolumn derivatization and chromatographic conditions for the resulting hexosaminitols are the same as those used for the analysis of amino acids. The method has been tested with as little as 2 micrograms of bovine fetuin, with a glycopeptide from bromelain and with an oligosaccharide after periodate oxidation.