A sensitive method for the determination of trace copper by preconcentration and adsorption of its 1-nitroso-2-naphthol complex onto the microcrystalline benzophenone has been developed. Several experimental conditions such as the pH of the solution, the quantities of 1-nitroso-2-naphthol and benzophenone, and the stirring time were optimized for effective separation. Trace copper in a 100 ml water sample was chelated with 2.0 ml of 0.050 M 1-nitroso-2-naphthol at pH 8.0. The solution was heated to 30 °C, stirred vigorously for 10 minutes to adsorb the copper complex quantitatively onto 0.20 g benzophenone. After the microcrystalline benzophenone adsorbed copper complex was filtered and dissolved in acetone, the content of copper was determined by flame atomic absorption spectrophotometry. The interfering effects of concomitant ions were investigated and almost eliminated. The detection limit and the determination limit of this method were 6.9 ngml−1and 22.9 ngml−1, respectively. Recoveries of 103.7 % and 94.2 % were obtained in a tap water and a brass sample, respectively. In the determination of copper in real samples, the values obtained by this proposed method were close to those by GF-AAS.