TOF - Time of flight mass analyzers are the simplest mass analyzers. TOF analysis is based on accelerating a group of ions to a detector where all of the ions are given the same amount of energy through an accelerating potential. Given the same push, lighter ions reach the detector before the heavier ones. Mass, charge, and kinetic energy of the ions affect the arrival time and the detector.

Unlike quadrupole instruments, electric field is not required to separate ions. MALDI-TOF/TOF or hybrid analyzers are extremely sensitive. TOF separates ions in space.

Reflectron

MALDI-TOF with reflectron is capable of detecting PSD. There are 3 kinds of reflectrons:

1. Single-stage mirror: poor fragment separation
2. Dual-stage mirror: High mass fragments enter the second stage offering good separation. Low mass fragments are reflected by the first stage practically without flight time dispersion.
3. Curved-field: High order energy correction, but low sensitivity and resolution (due to radial potential gradient).

PSD – Post Source Decay

Fragment analysis can be carried out using MALDI TOF/TOF by detecting PSD. PSD is achieved by applying twice the intensity of laser. Reflectron takes advantage of the fact that the fragment ions have different kinetic energies and separates them based on how deeply the ions penetrate the reflectron field, thus producing a fragment ion spectrum.

Prompt Fragmentation is fragmentation before the push through the TOF.