Gas phase fragmentation of protonated betaine and its clusters

Abstract

Betaine [(CH3)3N+CH2COO -] is a methylated version of glycine and is a zwitterion in its neutral form. In this work, we have subjected protonated betaine, +(CH3)3NCH2COOH, to a range of fragmentation experiments which involve vibrational excitation, electronic excitation and electron capture. Low-energy (eV) collisions in combination with deuterium labelling reveal that the lowest energy dissociation pathway is the formation of N(CH3)3+• and •CH 2COOH. The dominant channel after 50 keV collisions with molecular oxygen is the same as that after low-energy collisions; however, more fragmentation is seen which is most likely due to electronic excitation of the ions in the collision processes. S..