- Abstract t -Butyl nitrite, n -butyl nitrite, and isoamyl nitrite were irradiated in the 225–227 nm, 208 nm, and 450–455 nm wavelength regions. The resulting mass spectra at different laser intensities, as well as those obtained by electron impact (EI), were compared. The ion fragmentation pattern is strongly dependent on the wavelength but shows similarities for the different nitrites at the same wavelength. The fragmentation obtained by EI is different from that obtained via laser excitation. Mechanisms for the laser-induced fragmentation process are suggested and discussed.