TOF-MS is a method of mass spectrometry in which the mass to charge ratio is determined by the amount of time it takes to move between 2 points given a fixed amount of kinetic energy. This technique allows the measurement of very large and complex ions and means it is useful in analyzing biomolecules and large organic molecules. TOF systems are often coupled with Maldi (Matrix Assisted Laser Desorption and Ionization) which is a gentle ionization technique that also lends itself to large molecules.
- Low finale pressure in the time of flight chamber
- High reliability
- Low power consumption
How does it work?
Ions are held at one end of the flight tube and are then given a fixed amount of kinetic energy and the time is measured from when the ions are energized to when they are detected. Given the same amount of energy, the larger a molecule is, the slower it will move. In modern TOF systems ions are turned one or more times using "reflectrons" to effectively increase the length of the flight tube and thereby the sensitivity of the TOF. The ions typically travel 1m or more in the tube and therefore having high vacuum is critically important to the system.
TOF systems always require high vacuum and depending on the design and type may have multiple pressure regimes. One or more customized turbopumps may be required for an ideal performance. Typical flow rates are quite low so backing pump requirements often aren't as difficult as in some other types of MS. Rotary vane pumps, Scroll pumps and Diaphragm pumps could works depending on the requirements. Pfeiffer Vacuum also offers a wide range of gauges to measure the pressures in your system and fore line. Several interfaces are available to ensure a proper connectivity between the different Pfeiffer Vacuum products using only one controller for all devices.