A liquid-phase microextraction based on application of supramolecular solvent as a carrier for ferrofluid has been developed for the extraction and determination of three organophosphorus pesticides (OPPs). The ferrofluid was produced from combination of oleic acid coated magnetic particles and supramolecular solvent as the extractant solvent. Ferrofluid can be attracted by a magnet, and no centrifugation step was needed for phase separation. A response surface methodology (RSM) based on central composite design (CCD) was used for efficient optimization of the main variables in the extraction procedure. Under the optimum experimental conditions, the calibration curves found to be linear in the range of 0.5-400 μg L-1 with correlation coefficients ranging from 0.9967 to 0.9984. The intra-day and inter-day precision (RSD %) for 100 and 200 μg L-1 of each pesticides were in the range of 2.0–5.3 % and 2.6–5.7 %, respectively. The limit of detection (S/N = 3), ranged from 0.1 to 0.35μg L−1. The proposed method was successfully applied to the extraction and determination of organophosphorus pesticide residues in water and fruit juice samples.
