Collision-Induced Dissociation Of Hydrated Adenosine Monophosphate Nucleotide Ions: Protection Of The Ion In Water Nanoclusters

Fragmentation of singly charged anions of adenosine 5'-monophosphate (AMP(-)) induced by collisions with neutral atoms (Ne, Na) has been studied at a collision energy of 50 keV. The experiments were performed with isolated AMP(-) as well as with AMP(-) anions nanosolvated in a cluster with a given number m of water molecules. In the first case, the dominant fragmentation channels concern the loss of adenine, PO3- and H2PO4-. In the latter, loss of water molecules becomes the dominating process, and the AMP(-) ion is fully protected when m is larger than similar to 13. The observed fragment distributions are well described with the model of an evaporative ensemble.