FIGURE 3.

GRIL-LC/MS analysis of aniline-tagged HS and CS disaccharides. A, XIC chromatographs for aniline-tagged HS disaccharide standards resolved by LC/MS. The panels on the right show that the two 3-O-sulfated HS disaccharides D2S3 and D2S9 can also be resolved after aniline tagging as can the two N-acetylated isobaric isomers D0A6 and D2A0. The only standard not resolved was D0H0, which co-elutes with the salt peak, thus suppressing its ionic signature. B, XIC chromatographs for CS disaccharide standards after aniline tagging. The panel on the right expands the region where disulfated CS disaccharide standards elute showing partial separation of D2a6 and D0a10. The two isobaric isomers D0a4 and D2a0 did not separate under these conditions but can be easily distinguished by CID (see Fig. 7). All XIC traces were generated with the appropriate m/z values for the HS and CS disaccharides listed in Table 1.