Practice question

Effective MALDI matrices must absorb incident laser wavelength, co-crystallize homogeneously with analyte, and promote efficient proton transfer. Alpha-cyano-4-hydroxycinnamic acid, commonly abbreviated CHCA, is a cinnamic acid derivative exhibiting strong absorbance at 337 nm nitrogen laser and 355 nm Nd:YAG laser wavelengths. It provides excellent ionization efficiency and facilitates desorption of peptides and proteins up to several kilodaltons with high sensitivity and minimal adduct formation. Though sinapinic acid favors larger proteins, CHCA remains widely adopted in proteomics laboratories for protein mixtures, peptide mass fingerprinting, and routine quality control applications.