Degradation of Tryptophan by UV Irradiation: Influencing Parameters and Mechanisms

The chlorination of dissolved amino acids can generate disinfection by-products (DBPs). To prevent the formation DBPs, we examined UV-induced degradation tryptophan (Trp). In order to further understand impact UV on Trp, effects initial concentrations pH, temperature, NO3?, HCO3? and Cl? Trp removal were investigated, a mechanism was also proposed. results demonstrated that fitted pseudo first-order reaction kinetic model. mainly caused by direct degradation. apparent rate constant kobs decreased with increase in concentration increased increases pH temperature. thermal activation energy 19.65 kJ/mol. Anions water had significant influence Trp. NO3? contributed but inhibited rate. By electron paramagnetic resonance (EPR) spectroscopy, ·OH proven be formed during UV. Based intermediate products C11H15NO3, C10H15N C9H13N detected LC-MS-MS, pathway speculated.