Recent Progress of Two-step Laser Desorption/Laser Ionization Mass Spectrometry and Its Application

As a particular ionization technology, laser photoionization has been widely used in the field of the mass spectroscopy. Matrix assisted laser desorption ionization(MALDI), where only one laser is used, has become the standard method in the biological mass spectrometry. In this review, a new mass spectrometric method based on two lasers is introduced, i.e., Two-step laser desorption/laser ionization mass spectrometry (L2MS). Comparing this method with MALDI, no matrix is needed to add on the substrate to form a good cocrystallization with the sample. The power and the wavelength of two laser beams can be optimized independently to maximize the signal. The recent research progress on the two-step laser desorption/laser ionization mass spectrometry and its applications on the analysis of the amino acids and peptides, the environmental pollutants PAHs (polycyclic aromatic hydrocarbons), the chemical additives, the mineral composition and the metabolic products are introduced. Future prospect in this filed is provided in the end.