The kinetics and oxidation products (OPs) of tramadol (TRA), an opioid, were investigated for its oxidation with ferrate (Fe(VI)) and ozone (O-3). The kinetics could be explained by the speciation of the tertiary amine moiety of TRA, with apparent second-order rate constants of 7.4 (+/- 04) M-1 s(-1) (Fe(VI)) and 4.2 (+/- 0.3) x 10(4) M-1 s(-1) (O-3) at pH 8.0, respectively. In total, six OPs of TRA were identified for both oxidants using Qq-LIT-MS, LTQFT-MS, GC-MS, and moiety-specific chemical reactions. In excess of oxidants, these OPs can be further transformed to unidentified OPs. Kinetics and OP identification confirmed that the lone electron pair of the amine-N is the predominant site of oxidant attack. An oxygen transfer mechanism can explain the formation of N-oxide-TRA, while a one-electron transfer may result in the formation of N-centered radical cation intermediates, which could lead to the observed N-dealkylation, and to the identified formamide and aldehyde derivatives via several intermediate steps. The proposed radical intermediate mechanism is favored for Fe(VI) leading predominantly to N-desmethyl-TRA (ca. 40%), whereas the proposed oxygen transfer prevails for O-3 attack resulting in N-oxide-TRA as the main OP (ca. 90%).