Quaternary Ammonium Polymeric Ionic Liquid-based Effervescence-Enhanced Dispersive Solid-Phase Extraction for Determining Five Sulfonamides Antibiotics in Reclaimed Waters and Their Underlying Interaction Mechanisms

Herein, two kinds of quaternary ammonium polymeric ionic liquids (PILs) were prepared and rigorously characterized based on SEM, FT-IR and 1H NMR data. The PIL-based effervescence-enhanced dispersive solid-phase extraction (PILE-d-SPE) method was developed based on effervescent tablets containing PILs as extractants, tartaric acid as acid source, NaHCO3 as alkaline source, and water-soluble starch as filler. The positive charges on the surface of PILs and the negative charges on the surface of sulfonamide antibiotics (SAs) exhibited significant electrostatic attraction, thereby enhancing interactions between two PILs and SAs. P[VBTHEA]Cl exhibited higher extraction efficiency for five SAs than P[VBTEA]Cl, possibly because the structure of P[VBTHEA]Cl contained more -OH functional groups compared to P[VBTEA]Cl. Before and after extraction, the FT-IR spectra of the two PILs were significantly different from the O-H and C-H stretching-vibration peaks. DFT calculations show that the strong hydrogen bonds formed between P[VBTHEA]Cl and SDM, resulting in the highest binding energy and, consequently, the highest SDM extraction recovery rate. Overall, the H-bonding induction effect was inferred to be the main reason for the superiority of P[VBTHEA]Cl over P[VBTEA]Cl in extraction efficiency. By the one-factor-at-a-time approach, several important variables were optimized for determining SAs in reclaimed waters as follows: 200-mg PILs as extractant, 400-µL acetone as elution solvent, and 5-min elution. By integration with HPLC-DAD detection, this approach provided satisfactory analytical performance: low detection limit (0.19-0.32 μg/L) and appropriately fortified recovery (78.4-99.7%) for five SAs. Consequently, the P[VBTHEA]Cl-based E-d-SPE method presents environmental friendliness, time-saving, easy operation, and excellent analytical performance.