A microextraction method, based on the complexation of Cu(II) with N-Benzoyl-N,N-diisobutylthiourea, followed by phase separation by assistance of supramolecular solvents, was developed. The supramolecular solvent of tetrahydrofuran and 1-decanol enhanced the hydrogen bonding, in addition to the dispersion action leading to a quick phase separation with efficient preconcentration of copper(II) at trace levels. The developed procedure works at weak acidic medium (pH 3). The analytical parameters were optimized. The influence of concomitant ions on the recoveries of copper was also investigated. The proposed supramolecular-based procedure exhibits a limit of detection (LOD) of 0.46 mu g L-1 as well as quantitative recoveries from water certified reference materials. The proposed procedure was applied to the determination of copper at trace levels in water samples obtained from various sources in Turkey.