Thermal luminescence spectra of lysine and phenylalanine in O2 measured with a Fourier-transform chemiluminescence spectrometer

► A solid sample of Lys shows a thermal luminescence (TL) spectrum with a peak at ∼600 nm in O2 at 450 K but not in N2. ► No TL emission is observed from a solid sample of Lys·HCl salt in N2 or O2. ► A solid sample of phenylalanine shows no TL emission, while its dicyclohexylamine salt shows a TL spectrum with a peak at ∼660 nm. ► Interaction between the free NH2 group of amino acids and O2 molecules plays an important role for the TL emission.