Chirp dependent matrix-assisted laser desorption/ionization measurements of alkali metal adapted angiotensine II by using ultrashort laser pulses in the near IR regime

Matrix-assisted laser desorption/ionization (MALDI) with ultrashort laser pulses is reported in the near IR regime (central wavelength 800 nm). The used matrices show almost no absorption in this wavelength regime. This phenomenon is examined by applying different linear chirps leading to pulse durations up to several picoseconds and is compared with calculations based on a two photon transition. The results support the interpretation, that multiphoton absorption of the matrix molecules is a relevant factor by using ultrashort laser pulses. For characterization of the ionization process, the cationization and the fragmentation of the used analyte (angiotensine II) with potassium has been investigated in order to figure out the influence of the laser pulse properties. Thereto, the cationization and fragmentation tendency have been described in terms of laser pulse duration and energy.

Figure optionsDownload high-quality image (58 K)Download as PowerPoint slideResearch highlights▶ Pulse feature dependence of the MALDI-signal. ▶ Multiphoton absorption in the MALDI-Process. ▶ Cationization process of angiotensine II during MALDI.