Ion Mobility Results for PET, 300 K Data - obtained using the MALDI-Sector instrument

Arrival time distributions (ATDs) for the PET 2-mer, 3-mer, and 4-mer cationized by Li+, Na+, and K+ (M+PETn) obtained at a drift cell temperature of 300 K. Single, symmetric peaks are observed for all oligomers except one. For Li+PET3, two peaks appear in the ATD that are separated by ~25 μs (corresponding to a difference in cross-section of 22 ± 2 Å2) indicating that two different conformers are present. Also evident in the ATDs is the increase in drift time for oligomers with larger values of n, consistent with an increase in size and collision cross-section.
Experimental collision cross-sections for M+PETn at 300 K. From a series of ATD measurements, in which the drift voltage is changed, the mobilities of each oligomer can be accurately determined and converted to collision cross-sections. The data collected at 300 K is shown below.