MALDI-TOF Mass spectrometry is a methode to determine the mass of molecules by measuring their time-of-flight in a evacuated tube with no electric and magnetic fields. The method requires a "start" signal (laser pulse) and a "stop" signal which is created in a detector hit by the molecule at the end of the tube. The time-of-flight depends on the mass of the molecule.
The mass of a molecule is given in the unit "Da" (Dalton) which is roughly the mass of a proton (1.67 × 10-27 kg).
The following video illustrates this principle:
more information about MALDI-TOF MS
The "stop" signal in a time-of-flight mass spectrometer is created by the molecule hitting a detector. The commonly used standard detector is an ionizing detector where an electron is emitted from the surface of the detector when hit by the molecule (secondary electron emission). The quantum efficiency of emitting such a surface electron strongly decreases with decreasing molecule velocity, i.e. with increasing moelcule mass.
The CryoDetector of Metromol operates on a fundamentally different physical principle: the kinetic energy of the molecule hitting the detector is converted into internal energy ("heat") leading to a "temperature" rise of the detector.
The following animation describes the principle of the CrypDetector:
more information about CryoDetector
