Quality control of chondroitin sulphate used in dietary supplements

Abstract

Chondroitin sulphate (CS), a complex polysaccharide isolated from animal cartilage, is used as an ingredient in dietary supplements to support joint health and/or to treat osteoarthritis. Several low-quality CS raw materials were identified in marketed products of dietary supplements. For the evaluation of the quality of CS, we present here a capillary isotachophoretic method (cITP). As a leading electrolyte for the anionic analysis of CS, a mixture of 5 mM HCl + 10 mM glycine + 0.01% of 2-hydroxyethylcellulose of pH 2.8 was used. A solution of 10 mM citric acid served as the terminating electrolyte. On a series of CS raw material samples we proved that the cITP is a suitable method for this purpose.