Gas Chromatography-Mass Spectrometric Determinations of Iduronic and Glucuronic Acids in Glycosaminoglycans after Reduction of Carboxylic Group Using Sodium Borodeuteride

Abstract

A gas chromatography-mass spectrometry procedure for the determination of subnanomolar amounts of uronic acids derived from glycosaminoglycans (GAGs) is described. It involves stoichiometric reduction of carboxyl groups by sodium borodeuteride coupled with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and methanolysis in methanolic hydrogen chloride (1.0M) at 80°C for 24h followed by trimethylsilylation. The uronic acid compositions of commercially available GAGs, such as dermatan sulfate from pig skin, heparan sulfate from bovine kidney, and heparin from bovine intestinal mucosa, were investigated by the present method. The results were confirmed by the quantitative ¹H-NMR spectroscopy. The method is also applicable to complex samples such as human urinary GAGs.