Figure 2: Scheme of the procedure normally used for GAG analysis. The GAG of interest is digested by the enzyme chondroitinase ABC that produces a mixture of unsaturated disaccharides depending on the structure of the GAG. The different disaccharides are subsequently separated by TLC and characterized by negative ion MALDI-TOF MS. Of course, this method is also applicable to hyaluronan (HA) as well as chondroitin sulfate (CS). The molecular structures and the m/z ratios of two selected oligosaccharides are provided along with their mass spectra. Please note that “+CO” indicates the formation of the formyl ester because the separation of the carbohydrates was performed in the presence of formic acid [16].