In this study, a new Schiff base (H4TSTE) was synthesized and characterized by elemental analysis, FT-IR, NMR and MS spectral data. Liquid-liquid extraction process was performed for removal of Cu(II), Mn(II), Ni(II), Pb(II) and Zn(II) from aqueous solutions by means of H4TSTE. The extractions were investigated depending on the concentration of picric acid, metal ion and H4TSTE ligand. Response surface methodology (RSM) was first applied to optimize metal ion-binding properties of H4TSTE. The extraction efficiency was estimated to be >98% for all metals by models. Under the same conditions, the extraction efficiency was experimentally found to be >97% with a relative standard deviation within +/- 0.10 (N = 4), indicating the suitability of the models.