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QitTof™ MS


Ion trap (IT) and time-of-flight mass spectrometry (TOF MS) are two powerful analytic technologies with major benefits. Syagen has combined the pair into a single instrument called the QitTof™ that offers the best of both worlds. QitTof is the first commercially-available instrument to offer the MSn advantages of IT MS along with the high-speed data collection rates of TOF MSn. For the end user, this means an exciting new capability for high-speed molecular analysis.

Quadrupole ion traps (QITs) are an effective way for storing ions. The ions can then be mass analyzed by conventional IT MS using mass-selective instability scanning. In QitTof, the stored ions are pulsed into a reflectron TOF mass analyzer. This configuration offers powerful capabilities not available by IT MS or TOF MS alone. Syagen has refined this technology and adapted it into the company's proprietary ionization sources. The image below shows the path of an ion in a QitTof instrument.



General benefits of QitTof™
  • Capability for mass-selective ejection and for MSn analysis (QIT advantage).
  • Multichannel mass detection leading to efficient collection of all ions (TOF advantage).
  • Low noise because each mass peak is detected in a narrow time bin (TOF advantage).
Furthermore, in combination with photoionization (PI), the QIT can achieve high dynamic range because PI avoids ionization of common atmospheric constituents. As a result, the trap does not fill up with atmospheric ions. The combination of PI and QitTof MS is the foundation for Syagen’s FieldMate™ and FieldTracker™ instruments.

Specific benefits compared to other instruments
  • Compared to typical orthogonal-extraction TOF MS, the QitTof configuration has the potential for higher ion transmission efficiency and allows for MSn operation.
  • Compared to IT MS, the QitTof™ MSn provides:
  • Higher repetition rate because ions are pulsed out rather than scanned out of the QIT.
  • Higher dynamic range due to higher repetition rate operation and greater ion trap capacity.
  • Better ion mass accuracy.
High-Speed MSn
QitTof MS enables MS/MS and potentially MSn analyses at high repetition rates. This capability is very important when combining structure analysis with high-speed chromatography. A particularly important application in bioanalytical studies is the sequencing of peptides from protein digest mixtures. The enormously large number of proteins in a single cell line coupled with the little understanding of their identification and function places strong demand on instrumentation that can provide high-speed analyses.

The figure below shows an example of the capability to perform fast MSn on a transient sample, such as a fast chromatographic peak. In this example, a sample of methadone in methanol was injected directly into a Syagen PI / QitTof MS instrument. The instrument was set to automatically apply a collisional-induced dissociation (CID) waveform to specific ion masses when their intensities reached preset threshold values. The result below shows the methadone parent ion at m/z 310 fragmenting to a daughter ion at m/z 265. When the daughter reaches an intensity threshold, an additional waveform is played causing the m/z 265 ion to fragment to the m/z 105 ion.

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