Ozone-Oxidation Products of Ibuprofen and Toxicity Analysis in Simulated Drinking Water

In this study, we report the simulation of the ozone disinfection of drinking water in the presence of ibuprofen, its oxidative degradation products, and the acute toxicity analysis by luminescent bacteria bioassay. The results showed that the ibuprofen oxidation followed first-order kinetics. The ultra-performance liquid chromatography quadrupole time-of-flight mass (UPLC/Q-TOF-MS) analysis showed that the major oxidation products of ibuprofen were as follows: (i) 4-ethylbenzaldehyde, (ii) 2-[4-(1,2-dihydroxypropyl)-2-hydroxy carboxylic acid, (iii) 1-(4ethylphenyl)-2-methylpropanol, (iv) 1-(4-ethylphenyl)-2-methylpropanone, (v) 2-[4-(1-hydroxy-2methylpropyl)phenyl]isobutyl propionate, and (vi) 4-ethylbutyl benzene. A reaction mechanism for the ibuprofen oxidation was proposed based on the oxidative degradation products. The photobacterium phosphoreum toxicity tests showed that the toxicity of the ibuprofen oxidation products is higher than ibuprofen. Thus, the ozone-oxidation products of ibuprofen generate a higher risk of acute toxicity.