Membrane-based inverted liquid-liquid extraction of organochlorine pesticides in aqueous samples: evaluation, merits, and demerits

In this work, a membrane-based inverted liquid-liquid extraction method was developed for the extraction of organochlorine pesticides in aqueous samples. The sample was packed inside a membrane bag, and it was then immersed in an organic solvent. The extraction process was assisted by stirring. The sample containing the membrane bag can be easily separated after extraction, and the step of phase separation is omitted. The extracted analytes were determined by GC-MS/MS. The factors affecting the extraction process, such as extraction solvent, extraction time, sample pH, and salt addition, were properly optimized. Analytical figures of merit of the proposed method were determined under optimum extraction conditions. This method showed a good linear working range for all the selected OCPs from 0.25 to 80 ng/mL with coefficients of determination up to 0.9993. The LODs ranged from 0.03 to 0.08 ng/mL. Finally, the applicability of this method was tested for real water samples, and the relative recoveries were within an acceptable range (80.8-120.4%). This method has the potential to be used for the analysis of OCPs in routine analytical laboratories.