Rapid screening of airway secretions for fucose by parallel ligand-exchange chromatography with post-column derivatization and fluorescence detection

Fucose (6-deoxygalactose) is a constituent of airway mucous glycoproteins. In this paper we describe a high-throughput method for screening nasal lavage fluid samples and induced sputum samples for fucose. Fucose was released by hydrolysis with 0.5 M sulfuric acid at 100 degreesC for 4 h. After pH adjustment remaining proteins were removed by on-line dialysis. Chromatography was performed with two 300 mm x 7.8 mm i.d. Bio-Rad Aminex HPX-87H columns arranged in a box-car configuration. Post-column derivatization was performed with benzamidine under alkaline conditions. Fluorescence was monitored at an excitation wavelength of 360 nm, using an optical cut-off filter of 420 nm. The limit of quantitation for fucose was 40 muM (S/N = 3) in 300 muL nasal lavage medium, with use of a 20-muL injection loop. Relative standard deviation (RSD) values for intra and inter assay data were below 15% and 20%, respectively, at spike levels of 635 muM L-fucose. The method was used to monitor the fucose content of human airway secretions.