Determination of sodium chondroitin sulfate added in foods

A method was developed for the determination of sodium chondroitin sulfate (ChS) in foods such as salad dressings, mayonnaises and fish sausages. Alcian blue reagent was added to the sample solution extracted from these foods, and ChS was precipitated selectively as ChS-alcian blue. The precipitate was dissolved in monoethanolamine and determined colorimetrically at 615nm. In this method, the recoveries were 89.3-105.9% and the detection limits were 0.01% for salad dressings and mayonnaises, and 0.02% for fish sausages. For qualitative analysis, the precipitate obtained from the sample solution by adding excess methanol was solvolyzed with methanol-hydrochloride followed by trimethylsilylation. Capillary gas chromatography and gas chromatography-mass spectrometry were carried out to identify D-glucuronic acid formed from ChS.