Infrared ion spectroscopy in a modified quadrupole ion trap mass spectrometer at the FELIX free electron laser laboratory

We report on modifications made to a Paul-type quadrupoleion trapmass spectrometer and discuss its application in infrared ionspectroscopy experiments. Main modifications involve optical access to the trapped ions and hardware and software coupling to a variety of infrared laser sources at the FELIX infraredfree electron laser laboratory. In comparison to previously described infrared ionspectroscopy experiments at the FELIX laboratory, we find significant improvements in efficiency and sensitivity. Effects of thetrapping conditions of the ions on the IR multiple photondissociationspectra are explored. Enhanced photo-dissociation is found at lowerpressures in theion trap.Spectra obtained under reducedpressure conditions are found to more closely mimic those obtained in the high-vacuum conditions of an Fourier transform ion cyclotron resonancemass spectrometer. A gas-mixing system is described enabling the controlled addition of a secondary gas into helium buffer gas flowing into the trap and allows for ion/molecule reactions in the trap. The electron transferdissociation (ETD) option of themass spectrometer allows for IR structure characterization of ETD-generated peptidedissociation products.

Source: Review of Scientific Instruments - October 17, 2016 Category: Physics Authors: Jonathan Martens, Giel Berden, Christoph R. Gebhardt and Jos Oomens Source Type: research