UV photodissociation of trapped ions following ion mobility separation in a Q-ToF mass spectrometer.

An ion mobility mass spectrometer has been modified to allow optical interrogation of ions with different mass-to-charge (m/z) ratios and/or mobilities (K). An ion gating and trapping procedure has been developed which allows us to store ions for several seconds enabling UV photodissociation (UVPD).

synapt_analystThe instrument has been modified to enable overlap of the laser and the ion beam within the transfer cell region. A CaF2 window is installed on the upper vacuum flange of the time-of-flight (ToF) analyser and a custom size UV-enhanced aluminium coated reflecting mirror (Melles Griot, USA) is attached to a modified pusher assembly. This mirror is mounted at a 45 degree angle with respect to the ion beam direction. In this configuration the laser beam is collinear with the ion beam. A lens has been added in the optical path, creating a focal point at the entrance of the transfer cell (between the parts 6 and 7. This modification retains all the normal functionality of the Q-ToF analyser. The laser used for this study was a Continuum Minilite II set at 266 nm with a repetition rate of 10 Hz. The energies used range between 0.4 and 1 mJ per pulse. The overall transmission of the energy between the output of the laser and the entrance of the transfer cell was measured as 50%.


UV photodissociation of trapped ions following ion mobility separation in a Q-ToF mass spectrometer
Bruno Bellina,  Jeffery. M. Brown,  Jakub Ujma,  Paul Murray, Kevin Giles,  Michael Morris,  Isabelle Compagnon and Perdita. E. Barran.
Analyst, 2014,139, 6348-6351
DOI: 10.1039/C4AN01656D

Leave a Reply

Your email address will not be published.