Practice question

MALDI requires matrix compounds that isolate analyte molecules, absorb energy from pulsed laser typically 337 nm or 355 nm, and facilitate proton transfer. Strong ultraviolet absorption ensures efficient energy uptake, leading to rapid sublimation of matrix crystals and entrainment of analyte into gas phase without direct photochemical damage. High volatility would evaporate prematurely, non-reactivity alone insufficient, and fluorescence indicates emission rather than absorption. Common matrices like CHCA, DHB, and sinapinic acid all possess aromatic systems with high molar absorptivity at laser wavelength, enabling gentle desorption and ionization of peptides.