Bruker APEX-Qe 9.4T
Hybrid quadrupole-FTICR (Fourier transform ion cyclotron resonance) mass spectrometer, or FTMS. Electrospray and nanospray sources, pulsed valve, leak valve for gas phase ion-molecule reactions, ECD and IRMPD. A tunable UV-vis laser is coupled to the FTICR since Summer 2008.
Principle of operation
Fourier Transform Ion Cyclotron Resonance mass spectrometry (FTICR-MS) is based on the circular movement of charged particles in a strong magnetic field (cyclotron movement). The cyclotron frequency depends directly on the mass-to-charge ratio of the ions. The periodic movement of ion packets is recorded and converted to a frequency spectrum with a Fourier transform, which is converted to a mass spectrum after calibration. The major advantage of this ultrahigh resolution mass spectrometer (specification: 900,000 FWHM at m/z = 780) with high mass accuracy (2 ppm) is its ability to resolve interferences: for example, a peak at mass 800.000 Da can theoretically be distinguished from a peak at mass 800.001 Da. These performances make the technique highly valuable for multiresidue analysis. The other particularity of the FTICR mass spectrometer is that new fragmentation techniques can be used, such as infrared laser activation, or electron capture dissociation. These two techniques can be used in combination to fragment very large molecules such as whole proteins.
What do we use this instrument for?
The instrument will be mainly used for qualitative analysis and structure elucidation of small molecules, DNA, proteins and protein/DNA assemblies. Compared to traditional mass spectrometers, new paradigms for analysis have to be developed to exploit the high resolution/high mass accuracy capabilities. We also explore the use of H/D exchange in solution and in the ICR cell as a tool for protein and DNA structural studies. Photodissociation is performed using the tunable UV-vis laser.
- Pictures of the installation (Aug. 2005)
- FTICR-MS tutorial on Jon Amster’s website