Figure 7. Analytical potential of mobility-separating UVPD fragment ions in our tandem-TIMS instrument.

(A) The nested ion mobility / mass spectrum for m/z 960 to 1040 shows a plethora of mobility-separated fragment ions that are not identified by mass analysis alone. (B) – (L) Extracted mass spectra for selected fragment ions observed in (A) with assigned ion or charge state annotated. The analysis shows that the mobility-separation in TIMS-2 is capable of separating the various fragment ions to such an extent that their isotope patterns are essentially baseline resolved. Notice that the experimental data show isotope patterns that indicate overlapping fragment ions.