The quantitative spectrophotometric estimation of total sulfated glycosaminoglycan levels. Formation of soluble alcian blue complexes.

The formation of soluble complexes between alcian blue dye and sulfated glycosaminoglycans provides the basis for the quantitative spectrophotometric estimation of the total concentration of these polysaccharides. Samples containing microgram quantities of sulfated glycosaminoglycan are mixed with a stable dye solution prepared in 15% phosphoric/2% sulfuric acids and absorbance readings at 480 nm are compared to an appropriate standard curve. The method is rapid, convenient, and reproducible. Analyses are performed under conditions in which there is no interference from the non-sulfated glycosaminoglycan hyaluronic acid, or most other anionic macromolecules. In addition, estimations are not effected by small anions or individual monosaccharides. The method has been used for the determination of the purity of commercially available preparations of hyaluronic acid and for the estimation of the sulfated glycosaminoglycan content of various biological fluids including normal human urine and the synovial fluid of individuals with rheumatoid arthritis and osteoarthritis.