Fig. 6From: Amino acids chemical stability submitted to solid state irradiation: the case study of leucine, isoleucine and valineMass spectra of valine irradiated in absence of air at low mass range (a) and at normal mass range (b). The spectra were recorded in negative ion mode. The concentration was 10 mM in a solution 1:1 MeOH-AcNH4. The mass spectra for l-Val standard are reported in the Additional file 1 Back to article page