On the hydrogen loss from protonated nucleobases after electronic excitation or collisional electron capture
2009 (English)In: European journal of mass spectrometry, ISSN 1469-0667, Vol. 15, 681-688 p.Article in journal (Refereed) Published
In this work, we have subjected protonated nucleobases MH+ (M = guanine, adenine, thymine, uracil and cytosine) to a range of experiments that involve high-energy (50 keV) collision induced dissociation and electron capture induced dissociation. In the latter case, both neutralisation reionisation and charge reversal were done. For the collision induced dissociation experiments, the ions interacted with O2. In neutral reionisation, caesium atoms were used as the target gas and the protonated nucleobases captured electrons to give neutrals. These were reionised to cations a microsecond later in collisions with O2. In choosing Cs as the target gas, we have assured that the first electron transfer process is favourable (by about 0.1–0.8 eV depending on the base). In the case of protonated adenine, charge reversal experiments (two Cs collisions) were also carried out, with the results corroborating those from the neutralisation reionisation experiments. We find that while collisional excitation of protonated nucleobases in O2 may lead to hydrogen loss with limited probabilities, this channel becomes dominant for electron capture events. Indeed, when sampling reionised neutrals on a microsecond timescale, we see that the ratio between MH+ and M+ is 0.2–0.4 when one electron is captured from Cs. There are differences in these ratios between the bases but no obvious correlation with recombination energies was found.
Place, publisher, year, edition, pages
2009. Vol. 15, 681-688 p.
protonated nucleobases, neutralisation reionisation, charge reversal, electron capture induced dissociation
Research subject Physics
IdentifiersURN: urn:nbn:se:su:diva-33287DOI: 10.1255/ejms.1039ISI: 000272826100002OAI: oai:DiVA.org:su-33287DiVA: diva2:282890