MALDI-TOF MS

MALDI-TOF MS:
-consist of 3 components: (i) a specimen ionization chamber, within which the laser-based vaporization of the specimen takes place;
(ii) a time of flight mass analyzer; and
(iii) a particle detector

- sample is spotted onto a target
plate, along with a chemical matrix (5).
The matrix is selected for certain prop-
erties, including easy sublimation, e.g. α-cyano-4-hydroxycinnamic acid

-sample-matrix
mixture is pulsed with a laser, Ultra-
violet nitrogen lasers (337 nm)

- Laser irradi-
ation results in vibrational excitation of
the matrix and the ejection (desorption)
of analyte molecules surrounded by
clusters of matrix molecules, water, and
ions. Once desorbed, the matrix mole-
cules transfer protons to the analyte,
resulting in positively charged analyte
cations in the gas phase.

-accelerated
across an electric field within the ion-
ization chamber to a velocity that
depends on the mass-to-charge (m/z)
ratio of the analyte.