Simultaneous Distillation Extraction Coupled with Derivatization and GC-MS for Multi-Residue Determination of Phenolic Compounds in Wastewater
A simple, economical method for the multi-residue determination of phenolic compounds in wastewater was developed using simultaneous distillation extraction (SDE) combined with derivatization and gas chromatography-mass spectrometry (GC-MS). The effects of extraction time, salt concentration, and pH on extraction efficiency were investigated. Optimal recovery was achieved with the addition of 10 g·L−1 NaCl, adjustment of pH to 4, and extraction with dichloromethane for 2.5 h. Under these conditions, recoveries for spiked concentrations of 100 ng·L−1 and 1,000 ng·L−1 ranged from 58.92% to 91.08% (RSD 2.97%–8.60%, n=3) and 68.83% to 109.88% (RSD 3.06%–7.22%, n=3), respectively. Limits of quantification (LOQ) were between 8.46 and 59.67 ng·L−1, with good linearity over the range of 10.0–1,000 ng·L−1. The method integrates extraction and purification in a single step, reducing sample preparation steps and organic solvent consumption, while improving sample throughput and recovery. Derivatization enhances sensitivity, enabling the detection of ultra-trace phenolic multi-residues in complex matrices such as influent of wastewater treatment plants.