The use of collisional activation spectra in the discrimination of stereoisomeric permethylated disaccharides.

Collisional activation spectra of quasimolecular ions generated by chemical ionization can be used for the discrimination of stereoisomeric permethylated disaccharides. The best results have been obtained by using ammonia and trimethylamine as reagent gases. In the case of trimethylamine the presence of water seems to play an important role in order to obtain distinctive collisional activation spectra. The structural information obtained with the chemical ionization gases mentioned is complementary. A flow chart is presented for the identification of an unknown permethylated disaccharide.