Ion chromatographic method for the analysis of sulfate in complex carbohydrates

A procedure is described for the quantitation of sulfate in complex carbohydrates. Samples are taken to dryness in the presence of a small amount of sodium hydroxide and the sulfate is liberated by pyrolysis. Sulfate is then quantitated by single-column ion chromatography eliminating the interference by ions such as phosphate, chloride, sodium and calcium which frequently occurs with colorimetric methods. The reproducibility of the method is approximately 10%. This approach cannot be directly applied to glycoproteins because a portion of the sulfur in sulfur-containing amino acids appears to be converted to sulfate. However, this method can be used to measure sulfate in oligosaccharides of glycoproteins if the protein components are removed prior to analysis.