Sixteen TPs derived from the 9 pharmaceuticals investigated in this study were identified by the integrated screening method(Table 1). Eleven compounds were unequivocally confirmed with reference standards, while molecular structures were proposed for the remaining 5. Fig. 3 shows the time-trends of the 16 TPs. The time-trends of the parent compounds, together with
extracted ion chromatograms and mass spectra for both the parent compounds and the identified TPs are available as Supplementary Material.TPs were identified for all parent pharmaceuticals except naproxen. Although 6-O-desmethylnaproxen has previously been identified as a common microbial TP of naproxen [17–19], it was not found in this study. We attribute this to its further transformation under aerobic conditions which has been described by Quintana et al. [18].