4-Chloro-N-8-quinolinylbenzenesulfonamide (HL) was synthesised and characterised by elemental analysis, IR and FT-Raman spectroscopy. The synthesised reagent dissolved in toluene was used for copper(II) extraction from 1.0 mol dm(-3) KNO3. The experimental extraction data have been treated graphically and numerically and the complexes CuL2 and Cu(NO3)L have been proposed as being responsible for the metal extraction. Values of the corresponding stoichiometric extraction constants have been determined. (C) 2004 Society of Chemical Industry.