Separation and quantitation of enantiomeric 3,6-anhydrogalactoses by conversion to the corresponding diastereomeric acetylated sec-butyl 3,6-anhydrogalactonates

A method to determine the proportion of both enantiomers of 3,6-anhydrogalactose in a sample has been developed using methyl 3,6-anhydro-α-d-galactoside as a model compound. It involves an oxidative hydrolysis to obtain the corresponding aldonic acids, which are further converted to the acetylated diastereomeric sec-butyl esters. These are separated and quantified by GLC using a standard column for carbohydrate analysis; the procedure has been extended to seaweed polysaccharides.