Atmospheric pressure chemical ionization and fragmentation of aminomonosaccharides in H 2 O and D 2 O

Aminomonosaccharides (glucosamine, galactosamine, and mannosamine) in H 2 O and D 2 O were ionized by atmospheric pressure chemical ionization (APCI) and their fragmentation patterns were investigated to identify them. All the aminomonosaccharides showed the same fragment ions but their relative ion intensities were different. Major product ions generated in H 2 O were [M + H] + , [M + H – H 2 O] + , and [2M + H – 3H 2 O] + , while in D 2 O were [M D6  + D] + , [M D6  + D – D 2 O] + , and [2M D6  + D – D 2 O – 2HDO] + . At a high fragmentor voltage above 120 V, the relative ion intensities of the major product ions showed different trends according to the aminomonosaccharides. For the use of H 2 O as solvent and eluent, the order of the ion intensity ratio of [M + H – H 2 O] + /[2M + H – 3H 2 O] + was galactosamine > mannosamine > glucosamine. When using D 2 O as solvent and eluent, the order of the ion intensity ratios of [M D6  + D – D 2 O] + /[M D6  + D] + and [2M D6  + D – D 2 O – 2HDO] + /[M D6  + D] + was mannosamine > galactosamine > glucosamine. It was found that glucosamine, galactosamine, and mannosamine could be distinguished by the specific trends of the major product ion ratios in H 2 O and D 2 O. Copyright © 2009 John Wiley & Sons, Ltd.