History Matrix-assisted laser desorption/ionization

the term matrix-assisted laser desorption ionization (maldi) coined in 1985 franz hillenkamp, michael karas , colleagues. these researchers found amino acid alanine ionized more if mixed amino acid tryptophan , irradiated pulsed 266 nm laser. tryptophan absorbing laser energy , helping ionize non-absorbing alanine. peptides 2843 da peptide melittin ionized when mixed kind of “matrix”. breakthrough large molecule laser desorption ionization came in 1987 when koichi tanaka of shimadzu corporation , co-workers used called “ultra fine metal plus liquid matrix method” combined 30 nm cobalt particles in glycerol 337 nm nitrogen laser ionization. using laser , matrix combination, tanaka able ionize biomolecules large 34,472 da protein carboxypeptidase-a. tanaka received one-quarter of 2002 nobel prize in chemistry demonstrating that, proper combination of laser wavelength , matrix, protein can ionized. karas , hillenkamp subsequently able ionize 67 kda protein albumin using nicotinic acid matrix , 266 nm laser. further improvements realized through use of 355 nm laser , cinnamic acid derivatives ferulic acid, caffeic acid , sinapinic acid matrix. availability of small , relatively inexpensive nitrogen lasers operating @ 337 nm wavelength , first commercial instruments introduced in 1990s brought maldi increasing number of researchers. today, organic matrices used maldi mass spectrometry.