Photodegradation mechanism and influencing factors of asthma drug salmeterol under UV irradiation
With serious air pollution, heavy use of asthma drugs caused the accumulation in environmental water, which might pose a potential risk on the organisms. In this study, the ultraviolet photodegradation of asthma drug salmeterol (SX) and influencing factors were studied, meanwhile, the possible photolysis pathway and toxicity trends during the photolysis process were further discussed. The results showed that the photolysis of SX conformed to the pseudo-first order kinetic reaction and 1 O 2 dominated the photolysis process with contribution of 41.7 %. As the temperature, pH value and HCO 3 − concentration increased, SX photolysis rate accelerated. The presence of NO 3 − could also promote the SX photolysis rate but with to Cl 2 − the increase of NO 3 − concentration, the promotion reduced via OH quenching and stronger optical shielding. When Cl − concentration increased to 0.1 mM, the promotion effect of Cl − turned to inhibition due to the transformation of Cl to Cl 2 − . Moreover, the photolysis of SX was inhibited by the Fulvic acid (FA) through optical screening effect and free radical scavenging. Based on the nine intermediates predicted by UPLC-Q-TOF, three possible transformation pathways were proposed. Luminous intensity test of photobacterium phoshoreum T3 spp indicated the toxicity of the final reaction system was reduced through the ultraviolet irradiation.
危险品化学品经营许可证（带存储）