Instrumentation
Thermo LTQ Orbitrap XL
LC Ultra-performance Nanoscale Liquid Chromatography - nanoAcuity UPLC
(Link to Thermo Scientific Website)
A Thermo LTQ Orbitrap XL, obtained by Dr. Robert Lefkowitz with a grant from the Howard Hughes Medical Institute, has recently been installed in the Duke Proteomics Core Facility. This instrument is primarily used for Dr. Lefkowitz’s research, and provides complementary qualitative and quantitative MS/MS capabilities to the Q-ToF instrumentation also available in the Proteomics Core Facility.
The LTQ OrbitrapPrinciple of Operation (content from www.thermo.com)
The hybrid FT mass spectrometer combines a linear ion trap MS and the Orbitrap mass analyzer. Ions generated by API are collected in the LTQ XL followed by axial ejection to the C-shaped storage trap which is used to store and collisionally cool ions before injection into the orbitral trap. The ions transferred from the C-Trap are captured in the orbitral trap by rapidly increasing the electric field and the detection of the image current from coherent ion packets takes place after the voltages have stabilized. Signals from each of the orbital trap outer electrodes are amplified and transformed into a frequency spectrum by fast Fourier transformation which is finally converted into a mass spectrum.
The LTQ Orbitrap XL features a new collision cell to provide additional flexibility to any MS2 experiment. Ions can be selected in the linear ion trap and fragmented either in the ion trap (CID) or in the collision cell and further measured in the Orbitrap mass analyzer. For HCD (Higher Energy Collisional Dissociation) fragmentation ions are passed through the C-trap into the collision cell. The offset between the C-trap and HCD is used to accelerate the parents into the gas-filled collision cell. Normalized Collision Energy compensates for the mass-dependent energy deposition in HCD MS/MS experiments, providing reproducible data from instrument to instrument.
Based on the fast and highly sensitive Thermo Scientific LTQ XL™ linear ion trap and the patented Orbitrap technology, the LTQ Orbitrap XL hybrid FT mass spectrometers support a wide range of applications from routine compound identification to the most challenging analysis of low level components in complex mixtures.
LTQ Orbitrap XL Instrument Diagram: