The present paper outlines novel, simple and sensitive method for the determination of copper using spectrophotometry after separation and preconcentration by cloud point extraction. The cloud point methodology was successfully applied for copper determination after complexation with aluminon (triammonium salt of aurintricarboxylic acid), at pH 3.5. Copper(II) ions was quantitatively recovered in Triton X-114 after centrifugation. Acetonitrile (0.2 ml) was added to the surfactant-rich phase prior to its analysis at λ max 538 nm. The influence of analytical factors including complexing agent, buffer solutions, Triton X-114, temperature, heating time, centrifuge rate and time were examined and optimized. The analytical characteristics of the method (e.g. linear range, Ringbom concentration ranges, molar absorptivity, Sandell sensitivity, optimum limits of detection and quantification, enrichment factor, and improvement factors) were evaluated. Linearity was obeyed in the range of 7.5-220 ng/ml of Cu 2+ ion. The detection and quantification limits of the procedure were 2.2 and 7.4 ng/ml of Cu 2+ ion. The tolerance limits of some anions and cations were also examined. The procedure was applied to detect copper in environmental, water and biological samples.