Ion-ion proton transfer reactions of multiply-charged oligonucleotide cations

Multiply-charged cations derived from the positive ion electrospray of the oligonucleotide 5'-d(CT-TAGCGCTAAG)-3' were subjected to reactions with the (M-CF3)(-) and (M-F)(-) anions derived from perfluoro-1,3-dimethylcyclohexane in a quadrupole ion trap. Both single strand ions and double strand ions formed from the self-complementary oligonucleotide were studied. In analogy with the reactions of multiply-protonated proteins with the same anions, no adduct formation was observed and the data were consistent with exclusive proton transfer. No evidence for fragmentation was observed for either the single strand ions or the double strand ions, although a small degree of fragmentation of the latter species could not be precluded based on these results alone. The simple and well-defined chemistry associated with the ion-ion reactions of oligonucleotide cations with anions derived from PDCH is desirable for the charge-state manipulation of moderately-sized oligomers (up to roughly 100 residues) because PDCH anions possess a number of desirable characteristics for the production and storage of ion/ion reaction products with mass-to-charge ratios in the tens of thousands. (C) 1997 Elsevier Science B.V.