MALDI is known as the abbreviation for “Matrix Assisted Laser Desorption/Ionization” and this is soft ionization technique, which allows measuring molecular masses of individual compounds by converting them into charged ions from a large quantity of complex mixture. MALDI system combines with TOF MS, which is Time-of-Flight Mass Spectrometry. The mass analyzer helps to separate charged ions according to their mass to charge ratio (m/z). The time for ions travelling through a field in the tube can disperse the ions regarding to their m/z in a field-free drift path; therefore, the lighter one arrives to detector before the heavier one. MALDI-TOF MS/MS instrument is especially important in the studies and analysis of biomolecules such as peptides, proteins, saccharides, lipids, glycans, and nucleic acids.
The aim of usage matrix is to facilitate ionization process. There are commonly used crystallized small organic molecules MALDI matrix substances, which are 2,5-Dihydroxybenzoic acid (DHB), 4-Hydroxy-α-cyanocinnamic acid (HCCA), 2,5-Dihydroxyacetophenone (DHAP), Sinapinic acid (SA), 3-Hydroxypicolinic acid (HPA), 2,4,6-Trihydroxyacetophenone (THAP) and the reason of usage different matrices is depending on the sample for quantification.