Fragmentation of deprotonated d-ribose and d-fructose in MALDI—Comparison with dissociative electron attachment

Fast and metastable fragmentation of deprotonated d-fructose – A combined experimental and computational study

“…Now the branching ratio is about 2:1 in favour of the loss of C1 and C2. This fragment was earlier tentatively assigned to a cross ring cleavage exclusively leading to a charged fragment containing C1, C2 and C3 [12]. From the current data, however, it is apparent that, though to a lesser extent, also a negatively charged fragment containing C6 is formed.…”

“…In these experiments the fragmentation of the anionic monosaccharides was found to be characterized by pronounced site selectivity, i.e. in the course of fragmentation the negative charge tends to remain on the anomeric carbon atom [8,12]. It was also shown that this selectivity is not determined by the mode of ionization (free electron attachment or deprotonation, respectively), but rather by the time scale of the dissociation reaction [12].…”

“…This effect was attributed to DEA. Fragmentation studies on the isolated deprotonated sugars as well as ribose and deoxyribose in the respective nucleosides have also been conducted [12,13]. In these experiments the fragmentation of the anionic monosaccharides was found to be characterized by pronounced site selectivity, i.e.…”

“…in the course of fragmentation the negative charge tends to remain on the anomeric carbon atom [8,12]. It was also shown that this selectivity is not determined by the mode of ionization (free electron attachment or deprotonation, respectively), but rather by the time scale of the dissociation reaction [12]. Direct DEA along a repulsive state proceeds generally very fast (in the order of vibrational periods, i.e.…”

“…The characteristic fragmentation of deprotonated monosaccharides is a loss of different numbers of H 2 O molecules and cross ring cleavage via abstraction of carbon containing fragments consisting of CH 2 O units [4,12]. Due to the fairly simple composition of the monosaccharides, given by the CH 2 O repeatunit, conventional mass spectrometry on fragmentation of the native monosaccharides does not reveal much information on the underlying mechanism.…”