Another interesting observation is that, even among the controls at pH 7.1 (IH should have the same structure as CH, and IC as CC), the apparent gas-phase kinetic stability changes; we see a trend when ranking them according to thymine content (lower kinetic stability with higher T content, see Figure ), and we hypothesize this is linked to the larger CCS in T-rich sequences, itself linked to the fact that there are fewer non-specific intramolecular hydrogen bonds in strands containing thymines.