Fig. 2From: Amino acids chemical stability submitted to solid state irradiation: the case study of leucine, isoleucine and valineMass spectra of l-Leu irradiated under vacuum condition in positive ion mode at low mass range (m/z 15–200) (a) and normal mass range (m/z 50–800) (b). The irradiated l-Leu was dissolved into a solution 1:1 of MeOH-AcNH4 45 mM to obtain a concentration of 7.8 mM. The mass spectra for l-Leu standard are reported in the Additional file 1 Back to article page