In order to determine copper at trace level by flame atomic absorption spectrometry (FAAS), a supramolecular solvent-based liquid-phase microextraction method has been developed. 1-(2-pyridylazo)-2-naphthol (PAN) was used as a chelating agent to obtain the copper complex. In this method, supramolecular solvent was prepared by using tetrahydrofuran (THF) and decanoic acid. pH, THF volume, amount of decanoic acid, amounts of chelating agent, ultrasonic bath and centrifugation time, matrix effects and sample solution volume parameters which were effective on the recovery of the method were optimised. The detection limit (LOD) and quantification limit (LOQ) were 7.30 mu g/L, 24.2 mu g/L, respectively. The preconcentration factor was found to be 40. The accuracy of the method was determined by analysing TMDA 53.3 and TMDA 64.2 certified reference materials and some addition recovery tests. The presented method was applied to urine, sweat, dialysis solution and water samples to determine their copper level by flame atomic absorption spectrometry (FAAS).