A cloud point extraction procedure was presented for the preconcentration of copper(II) ion in various samples. After complexation by 4-(phenyl diazenyl) benzene-1,3-diamine (PDBDM) (chrysoidine), copper(II) ions were quantitatively recovered in Triton X-114 after centrifugation. 0.5 ml of methanol acidified with 1.0 mol L-1 HNO3 was added to the surfactant-rich phase prior to its analysis by flame atomic absorption spectrometry (FAAS). The influence of analytical parameters including ligand. Triton X-114 and HNO3 concentrations, bath temperature, heating time, Centrifuge rate and time were optimized. The effect of the matrix ions on the recovery of copper(II) ions was investigated. The detection limit (3S.D.(b)/m, n = 10) of 0.6 ng mL(-1) along with preconcentration factor of 30 and enrichment factor of 41.1 with R.S.D. of 1.0% for Cu was achieved. The proposed procedure was applied to the analysis of various environmental and biological samples. (C) 2008 Elsevier B.V. All rights reserved.