## 3 Results and Discussion
### Occurrence of PhACs in the Five WWTPs and Surface Waters  
The discussion is focused on concentrations and detection frequencies of PhACs in the influent and effluent of target WWTPs (Table 3), and the values obtained upstream and downstream of the target WWTPs (Table 4). Both tables show the obtained results organized by minimum concentration (Min), maximum concentration (Max), median concentration (Med), percentage of positive samples (% Pos), and detection frequency (Freq) in influents (or upstream) and effluents (or downstream) of the five WWTPs of the Evora district. The Freq is equal to the number of positive samples divided by the number of studied WWTPs. All PhACs not detected in the water samples (<MQL) were excluded from the statistical analysis. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**PhACs**} & \begin{tabular}{c} **Working** \\ **Range** \\ **(\#g/L)** \\ \end{tabular} & \begin{tabular}{c} **R2** \\ **(\#g/L)** \\ \end{tabular} & **CV\({}_{\text{m}}\) (\%)** & **PG** & \begin{tabular}{c} **MDL** \\ **(ng/L)** \\ \end{tabular} & \begin{tabular}{c} **MQL** \\ **(ng/L)** \\ \end{tabular} & \begin{tabular}{c} **Rec** \\ **(\%)** \\ **(\#g/L)** \\ \end{tabular} & \
\begin{tabular}{c} **RSD** \\ **(\%)** \\ \end{tabular} &
\begin{tabular}{c} **U** \\ **(\%)** \\ \end{tabular} \\ \hline \multicolumn{10}{c}{**Acidic method**} \\ \hline ATN & 0.76–7.1 & 0.9998 & 4.14 & \(-\)0.49 & 40.5 & 12.3 & 75.1 & 15.0 & 29 \\ APAP & 0.79–7.3 & 0.9993 & 4.75 & 1.31 & 42.4 & 12.9 & 74.5 & 12.8 & 28 \\ SDZ & 0.84–7.8 & 0.9996 & 2.87 & 0.04 & 41.9 & 12.7 & 80.1 & 7.61 & 30 \\ SPD & 0.77–7.1 & 0.9997 & 1.58 & 0.34 & 36.7 & 11.1 & 84 & 9.41 & 31 \\ CAF & 0.8–7.4 & 0.9996 & 5.21 & 1.71 & 29.9 & 9.06 & 107 & 13.2 & 24 \\ SMX & 0.77–7.2 & 0.9998 & 1.55 & 0.17 & 31.2 & 9.46 & 98.7 & 7.41 & 29 \\ MTPL & 0.76–7.1 & 0.9999 & 3.53 & 0.27 & 29.2 & 8.86 & 104 & 14.8 & 34 \\ PPNL & 0.79–7.3 & 0.9996 & 4.48 & 1.81 & 53.9 & 16.3 & 58.6 & 8.99 & 42 \\ CTS & 0.78–7.3 & 0.9998 & 1.64 & 0.03 & 42.4 & 12.8 & 73.6 & 6.13 & 31 \\ CBZ & 0.78–7.3 & 0.9998 & 2.51 & 0.85 & 57.7 & 17.5 & 54.1 & 0.68 & 29 \\ CFA & 4.2–39 & 0.9997 & 2.34 & 5.76 & 140.0 & 42.4 & 120 & 16.7 & 29 \\ NPX & 0.77–7.2 & 0.9999 & 2.90 & 2.45 & 31.5 & 9.54 & 97.8 & 9.61 & 26 \\ GTD & 0.78–7.3 & 0.9993 & 6.66 & 5.79 & 71.1 & 21.5 & 43.9 & 1.32 & 35 \\ TTE & 0.75–7.0 & 0.9995 & 4.23 & 1.24 & 53.5 & 16.2 & 56.1 & 10.1 & 38 \\ \hline \multicolumn{10}{c}{**Basic method**} \\ \hline BZF & 0.75–7.0 & 0.9996 & 1.93 & 1.55 & 26.3 & 7.98 & 113.9 & 18.2 & 36 \\ IBUP & 1.6–14.5 & 0.9999 & 1.59 & 3.53 & 66.4 & 20.1 & 96.4 & 8.01 & 28 \\ DCF & 0.77–7.2 & 0.9997 & 3.75 & 0.003 & 22.5 & 6.81 & 137 & 4.14 & 13 \\ E1 & 10.1–94 & 0.9997 & 3.91 & 2.94 & 735.9 & 223.0 & 54.9 & 13.9 & 35 \\ E3 & 7.19–67 & 0.9999 & 1.70 & 0.98 & 284.8 & 86.3 & 101 & 17.8 & 23 \\ E2 & 9.02–84 & 0.9983 & 5.78 & 0.08 & 560.2 & 169.8 & 64.4 & 18.1 & 35 \\ EE2 & 9.24–86 & 0.9990 & 2.62 & 5.81 & 658.8 & 199.6 & 56.1 & 13.4 & 40 \\ DES & 9.27–87 & 0.9985 & 5.94 & 0.3 & 435.2 & 131.9 & 85.2 & 13.8 & 41 \\ ERT & 1.58–15 & 0.9994 & 6.23 & 6.04 & 44.2 & 13.4 & 143 & 23.8 & 40 \\ FLX & 1.51–14 & 0.9992 & 4.88 & 0.99 & 37.8 & 11.4 & 160 & 19.5 & 32 \\ CLR & 1.52–14 & 0.9994 & 5.76 & 0.35 & 87.1 & 26.4 & 69.8 & 13.0 & 38 \\ AZM & 1.51–14 & 0.9993 & 3.25 & 1.90 & 96.0 & 29.1 & 62.9 & 17.6 & 33 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Working range, method detection, and method quantification limits (MDL, MQL), recovery (Rec, %) and relative standard deviation (RSD, %), and expanded uncertainty (U, %) of SPE-LC-MS/MS method.