MSFig. 1. Summary of the procedural performance of the integrated screening met hod applied to the experiment with initial concentration of 500 g L−1. In step I, number srefer to the peaks remaining after each step; in step II, numbers refer to the peak intensity values for each entry; in step III, numbers before and after the slash refer to negative and positive ionizati on mode, respectively, numbers in the square bracket srefer to the same compounds detected in the opposite ionization mode, numbersin round brackets refer to fragments and/or adducts, an example is shown in the figure data, as illustrated in Fig. 1 for the experiment with an initial concentration of 500 g L−1. In both ionization modes, step I eliminated approximately 97% of the detected peaks, with a majority being class ified as noise (i.e. intensity below threshold). 80% of there maining peaks were discarded based on the time-trend criterion.Overall, less than 1% of the initial peaks were passed on to step IIIfor further processing and structure assignment. Eleven promisingcomponents corresponded to a UM-PPS prediction and another 5corresponded to a literature record. Only 4 candidate componentsin negative mode and 2 in positive mode (Fig. S2, SupplementaryMaterial) remain unknown. No prediction could be matched toone of these components, and no characteristic diagnostic struc-tural features (e.g., neutral CO2-loss) were observed in the massspectra that could provide a link to a specific parent compound.For these potential TPs, elemental compositions were generatedfrom their measured exact mass and isotopic patterns by the toolimplemented in the instrument software (Tab. S3, SupplementaryMaterial). Incubation experiments with individual pharmaceuticalswould be necessary for further exploring the identity of these TPs.