Optimization of the ionic liquid-based dispersive liquid–liquid microextraction combined with high-performance liquid chromatography coupled with diode array detection for the determination of multiclass pesticide residues in water samples

Abstract

An expeditious and effective analytical methodology, predicated on ionic liquid-based dispersive liquid–liquid microextraction (IL-DLLME) integrated with high-performance liquid chromatography coupled with diode array detection (HPLC-DAD), has been devised for the quantification of multiclass pesticides in aquatic samples. This methodology employs 1-Hexyl-3-methylimidazolium hexafluorophosphate ([C₁₀H₁₉N₂][PF₆]), 1-Octyl-3-methylimidazolium hexafluorophosphate ([C₁₂H₂₃N₂][PF₆]), and 1‑butyl‑3-methylimidazolium hexafluorophosphate ([C₈H₁₅N₂][PF₆]) as the extraction solvent and utilizes methanol as the disperser solvent. Critical parameters influencing the efficacy of the extraction, encompassing the type and volume of extraction and disperser solvents, sample pH, and vortex conditions, were meticulously optimized. Under optimal conditions, the methodology exhibited commendable linearity (0.9974 ≤ R² ≤ 0.9996), minimal limits of detection (0.1–1.3 µg/L) and quantification (0.3–3.9 µg/L), as well as satisfactory precision (relative standard deviation (RSD) ≤ 9.6 %). The methodology was adeptly applied to the analysis of tap water, groundwater, and river water samples, yielding recoveries spanning from 85 % to 105 %. The findings substantiate that IL-DLLME represents an auspicious technique for the extraction and quantification of multiclass pesticides in intricate aqueous matrices.