Identification of degradation products of erythromycin A arising from ozone and advanced oxidation process treatment.

The degradation products of the macrolide antibiotic erythromycin A (ERY) arising from direct ozone attack and hydroxyl radical attack are presented for the first time. Ozone treatment was carried out by spiking ozone stock solutions to solutions containing ERY-ERY:O3 = 1:5 and 1:10 (M:M), while, in parallel, t-BuOH was used as a hydroxyl radical (*OH) scavenger. The advanced oxidation processes (AOPs) O3/UV, O3/H2O2, and UV/H2O2 were carried out to recognize and verify possible differences between their primary degradation products; the initial concentrations were ERY:O3 = 1:5 (M:M), ERY:O3:H202 = 1:5:5 (M:M:M), or ERY:H202 = 1:5 (M:M), respectively.