Chromatographic silica (10 mu m) was chemically modified with the silylating agent: [3-(2-aminoethyl)aminopropyl] tri methoxysilane (AEAPTS). The reaction product was characterized bg elemental analysis and infrared and C-13 and Si-29 NMR spectra, The chemically modified silica was treated with Cu(II) in methanol medium. This cation was strongly adsorbed through complexation by the pendant ethylenediamine groups attached to the silica surface, The complex formed on the silica surface was shown to be stable in both aqueous and non-aqueous media. The aim of Cu(II) immobilization is to use this new material as a stationary phase in High Performance Liquid Chromatography (HPLC), Separations of synthetic mixtures of aromatic amines and of polyaromatic hydrocarbons were undertaken using 150 x 3.9 mm HPLC columns parked with the modified silica, with and without copper ions, to follow the influence of the cation on the chromatographic separation and to verify the efficiency of the new stationary phase for HPLC.222103108