A Cloud point extraction procedure was presented for preconcentration of Cu (II) after complexation by new azo reagent 4-(Nitro phenylazo imidazole) (NPAI) are quantitatively extracted in Triton-x-114 following separation, prior to its analysis by UV-Vis Spectrometry. The experimental conditions such as pH, concentration of Triton-x- 114, temperature, time of heating, stoichiometry for complex extracted were studied .Under the optimum established conditions, the detection limit of 0.045μg mL-1 of Cu (II) and concentration range of 0.1-5 μg mL-1, the molar absorption 2.85x104 L.mol-1.cm-1. The precision for seven replicate measurements of 5μg mL-1Cu (II) was of 0.30%. The method was applied to the determination of copper in amalgam dental material sample by CPE technique and comparing the result with atomic spectroscopy.