B Farajmand - Department of Chemistry,University of Zanjan, Zanjan, Iran
H Bahrami - Department of Chemistry,University of Zanjan, Zanjan, Iran

Threonine is proteinogenic amino acids bearing an alcohol group in the side chain.Theoretical and experimental studies had been done on the structure, properties andfragmentation of Threonine [1]. Because of its scientific and medical interest, the structuralelucidation of Threonine using electron ionization mass spectrometry (EI–MS) had beenconducted [2]. However, the interpretation of mass spectra is typically performed bytheoretical calculations. Appearance energies (AE) is a valuable tool in mass spectrometry forthe evaluation of thermodynamic properties of ions, neutral molecules and fragments.