Effect of the target on the efficiency of generation of monomolecular ions of fluorine-containing amino acids in laser desorption/ionization

A comparative analysis was carried out on the laser desorption/ionization (LDI) mass spectra of fluorine derivatives of N-phenylphenylglycine using different targets. The extent of generation of molecular ions of the fluorine-containing amino acids was shown to depend significantly on the nature of the target surface. Alkali metal chlorides (LiCl, NaCl, KCl, and CsCl) have the highest efficiency among the targets studied (standard metal target, polished monocrystalline silicon, glass, silica) in the generation of molecular ions of fluorine-containing amino acids, which increases in the series LiCl < NaCl < KCl < CsCl.