## 3 Results and Discussion
### Analytical Protocol Parameters  
The analytical parameters of each compound (i.e., the correlation curve and relative correlation coefficient r, the limit of detection (LOD), the limit of quantification (LOQ), reproducibility, and precision) were studied by applying the best experimental conditions to a real sample. Briefly, the optimal conditions are as follows: 200 uL of \(n\)-hexane, used as extraction solvent, and 5 uL of anthracene (1 mg mL\({}^{-1}\)) are added to 1 L water sample (pH solution 5), followed by 5 min stirring time and 6 min ultrasonic bath and addition of NaCl 15 g L\({}^{-1}\), vortex for 10 min, and injection of 1 uL of the final solution. The analyte extraction procedure was performed using the dispersive liquid-liquid microextraction (DLLME) method. This step offers two advantages: the dispersive solvent, which substantially allows and simplifies the dispersion of the extraction solvent, is not used (replaced by the ultrasonic bath step) and, more importantly, an average pre-concentration factor of 5000. Table 2 shows all the analytical parameters obtained using the best experimental conditions, namely, the linear equations and the relative correlation coefficients (r) studied in the linear dynamic ranges (LDRs) along with the limit of detection (LOD) and the limit of quantification (LOQ) of each compound. These values were determined according to [PERSON]'s definition [69], that is, an analyte concentration that produces a chromatographic peak is equal to three times (LOD) and seven times (LOQ) the standard deviation of the baseline noise (this definition is based on the signal-to-noise approach). Table 3 shows the recoveries for each compound at different concentrations and the intra-day and inter-day precisions calculated by adding different PAE/BPA amounts to real water samples. The recoveries were determined at two different concentrations, namely, at low, 30 ng mL\({}^{-1}\), and high, \begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Compound**} & **Blank Solution** & **Real Sample** \\ \cline{2-3}  & **\% \(\pm\) SD (RSD)** & **\% \(\pm\) SD (RSD)** \\ \hline DMP & 99.1 \(\pm\) 2.1 (2.1) & 97.5 \(\pm\) 3.5 (3.6) \\ DEP & 99.6 \(\pm\) 1.6 (1.6) & 97.9 \(\pm\) 5.9 (6.0) \\ DBP & 98.5 \(\pm\) 3.1 (3.1) & 98.8 \(\pm\) 8.6 (8.7) \\ DBP & 99.1 \(\pm\) 3.5 (3.5) & 98.4 \(\pm\) 3.3 (3.9) \\ BPA & 97.2 \(\pm\) 4.3 (4.4) & 95.1 \(\pm\) 6.2 (6.5) \\ DEHP & 97.9 \(\pm\) 2.6 (2.4) & 96.3 \(\pm\) 5.2 (5.4) \\ DOP & 99.7 \(\pm\) 1.7 (1.7) & 98.2 \(\pm\) 4.1 (4.2) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Evaluation (in terms of % recoveries) of the entire analytical procedure on the matrix effect comparison between a distilled water solution and a tap water sample (SD, standard deviation), both spiked with the same mixed PAE/BPA standard solution (80 ng mL\({}^{-1}\) of each compound) (RSDs are reported in brackets). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Compound**} & **LDR** & \multirow{2}{*}{**Correlation Curve**} & **LOD** & **LOQ** & **Limit** \\  & **(ng mL\({}^{-1}\))** & & & **(ng mL\({}^{-1}\))** & **(ng mL\({}^{-1}\))** & **Limit** \\ \hline DMP & 6–1500 & \(y=\) 2.860x + 0.516 & 0.9944 & 1 & 6 & 5.0\({}^{\text{a}}\) \\ DEP & 11–1500 & \(y=\) 1.810x + 0.130 & 0.9983 & 4 & 11 & 0.55\({}^{\text{a}}\) \\ DBP & 6–1500 & \(y=\) 1.984x + 0.227 & 0.9933 & 3 & 6 & 0.01\({}^{\text{b}}\) \\ DBP & 5–1500 & \(y=\) 2.494x + 0.212 & 0.9981 & 2 & 5 & 0.45\({}^{\text{a}}\) \\ BPA & 9–1500 & \(y=\) 2.102x + 0.295 & 0.9961 & 5 & 9 & 50\({}^{\text{c}}\) \\ DEHP & 9–1500 & \(y=\) 2.392x + 0.258 & 0.9972 & 1 & 9 & 6\({}^{\text{d}}\) \\ DOP & 14–1500 & \(y=\) 2.014x + 0.253 & 0.9979 & 8 & 14 \\ \hline \hline \end{tabular} \(\text{a}\), threshold limit value (TLV) expressed as mg L\({}^{-1}\) (US EPA, reference [70]); b, expressed as mg kg\({}^{-1}\) day/b.w. (EFSA, ref. 31); c, as ug L\({}^{-1}\) (from the U.S. Food and Drug Administration, FDA); d, as ug L\({}^{-1}\) (from the World Health Organization, WHO).  
\end{table}