• • Optimal SDE conditions: 10 g·L−1 NaCl, pH 4, 2.5 h extraction with dichloromethane, yielding recoveries of 58.92%–91.08% (100 ng·L−1 spike) and 68.83%–109.88% (1,000 ng·L−1 spike), with RSD ≤8.60% (n=3). This ensures reliable quantification in complex wastewater matrices.
• • LOQ values of 8.46–59.67 ng·L−1 (S/N=9) and linear range of 10–1,000 ng·L−1 enable detection of phenolic compounds at concentrations below odor thresholds (4–500 ng·L−1), critical for environmental risk assessment.
• • Compared to the national standard HJ744-2015 (liquid-liquid extraction), the SDE method achieves comparable or better recoveries (68.83%–109.88% vs. 65.7%–105%) while simplifying steps and reducing solvent use, lowering cost and labor.
• • The method successfully detected phenolic multi-residues in influent samples from five wastewater treatment plants in Beijing, demonstrating its applicability to real-world complex matrices.