Infrared multiphoton dissociation: An alternative to collision-induced dissociation

ANYL 359

Gary L. Glish, glish@unc.edu, Department of Chemistry, University of North Carolina at Chapel Hill, CB# 3290, Chapel Hill, NC 27599
Collision-induced dissociation is by far the most common method used to perform MS/MS experiments and while it is typically quite efficient in a quadrupole ion trap, there are some key limitations. Most notably once the parent ion dissociates, the product ion is no longer in resonance with the excitation voltage and thus limited consecutive dissociation occurs. This is in contrast to beam type instruments such as triple quadrupoles and quadrupole/time-of-flight instruments where consecutive dissociation can lead to much more structural information. One way to obtain more structural information in a quadrupole ion trap is to perform MSn experiments. Alternatively, infrared multiphoton dissociation (IRMPD) in a quadrupole ion trap is a non-selective activation/dissociation process so product ions can readily undergo subsequent dissociation. However, cooling of the activated ions by collisions with the He bath gas can limit the dissociation. In this presentation the fundamentals of the IRMPD experiment will be discussed.