Multivariate optimization of dispersive liquid-liquid microextraction solvent-based for the determination of organochlorine pesticides in water by gas chromatography coupled to mass spectrometry

In this work, a dispersive liquid-liquid microextraction (DLLME) method was optimized for the determination of organochlorine pesticides in water samples, including surface water. Chloroform was used as the extraction solvent, and acetone was used as the dispersive solvent. Initially, solvent selection was performed univariately. Subsequently, key parameters, such as the type of extraction solvent, temperature, and volumes of extraction and dispersive solvents, were optimized using a full factorial design. The optimized conditions included an extraction temperature of 5 and 20 °C, and an extraction solvent volume of 25 μL and 50 μL. Coupled with gas chromatography-mass spectrometry (GC-MS), the method demonstrates detection limits ranging from 1.16 to 9.91 ng L⁻¹ and quantification limits from 3.51 to 30.0 ng L⁻¹. The developed method proved effective for detecting organochlorine pesticides (α-BHC, β-BHC, γ-BHC, Heptachlor, Heptachlor epoxide, Aldrin, Dieldrin, 4,4′-DDE, 4,4′-DDD, and 4,4′-DDT), offering a simple and efficient alternative for environmental monitoring and analysis.