N-propylsalicylaldimine based on porous silica, as ion exchanger, is used for the separation and preconcentration of Fe3+, Co2+, Ni2+ and Zn2+ from surface water samples collected from eleven locations at Nile river, Mediterranean and Red seas and Mansoura city tap water. The effects of pH, time of stirring, concentration of eluting acids and sonic common ionic species on the separation and preconcentration of the investigated metal ions in synthetic aqueous solutions are studied. The results indicate that the optimum conditions for separation are pH = 9.0-9.5 and time of stirring = 30 min. HCl is better eluent for the investigated metal ions than HNO3 except for Fe3+. Citrate and EDTA show severe interference on the recovery of the metal ions, therefore, the water samples are previously oxidized to digest organic matter prior to the application process.