Spectrométrie de masse MALDI-TOF

MALDI-TOF mass spectrometry is an analytical technique for detecting and characterizing biological samples such as peptides, carbohydrates, and DNA.

MALDI-TOF contains an ionization source to generate gaseous ions and a mass analyzer for ion detection based on the ion’s time of flight. 

First, the sample peptides are mixed with a matrix and loaded onto the target plate.

When struck by a laser, the sample desorbs, producing positively charged ions. That is why this technique is called, matrix-assisted laser desorption ionization.

Ions then move into the mass analyzer, where they are sorted, depending on the time required to travel through the length of the flight tube.

This time of flight is proportional to the square root of the mass-to-charge ratio. Among the ions with the same charge, smaller ions move faster.

The detector collects these ions and passes the information to a computerized system. It generates a peptide mass fingerprint to identify the unknown protein by comparing the peptide fragments with a database library.