MALDI is a mass spectrometric ionization technique in which a chemical matrix is mixed with a sample and allowed to dry into a co-crystalline structure. A laser is fired at spots of the co-crystal where the absorbed energy ionizes the sample components and releases them for detection. Time-of-flight is a type of mass analyzer often combined with MALDI. in time-of-flight, the mass-to-charge ratio of an ion is determined by the time it takes for the ion to travel through a flight tube from the ion source to the detector. The mass of the target molecule is equal to the detected mass divided by the charge of the ionized target (mass/charge, m/z)
Mass detection by time of flight is more accurate than that of other mass spectrometer detectors and has a large detection range, commonly 50-150,000 Da. For this reason, it is often paired with MALDI for the detection of complex bio-molecules especially proteins, peptides, and oligosaccharides.