Magnetite nanoparticles with an average particle size of 28.8nm were synthesized, coated with oleic acid, and characterized using various techniques such as DLS, FT-IR, SEM, XRD, VSM, and UV-Vis analysis. A nanofluid consisting of synthesized nanoparticles and 5 wt % acetic acid in toluene as the dispersed phase was prepared and used in the chemical test system, Toluene-Acetic Acid-Water, for the single drop extraction in the presence and absence of an external oscillating magnetic field. Influences of various operating and design parameters such as nanoparticle concentration, drop diameter, and the applied current and frequency on the overall mass-transfer coefficients for the mass-transfer direction from dc were investigated carefully. The obtained results were used to propose a general correlation for the mass-transfer enhancement. It was found that the maximum mass-transfer enhancement compared with that obtained in the absence of nanoparticles and the oscillating magnetic field is about 259%. (c) 2016 American Institute of Chemical Engineers AIChE J, 62: 4466-4479, 2016