A cellulose acetate membrane filter was applied for solid-phase extraction of Cd(II), Co(II), Cu(II), Fe(III), Ni(II), and Pb(II) from urine, hair, fish, and various water samples. The analyte ions were adsorbed on membrane filter as Cochenille red complexes and then eluted using 10 mL 3 M CH3COOH. The matrix effects from concomitants and analytical parameters, including pH, sample volume, membrane type, and flow rates, were investigated. The analyte ion detection limit for the proposed method was in the range 1.0-5.2 mu g/L. The preconcentration factors were calculated as 30 for Cu(II), 40 for Co(II), Ni(II), Cd(II) as well as Pb(II), and 50 for Fe(III). The proposed method was validated by analyzing certified reference materials. This method was successfully applied to water, hair, fish, and urine samples with good results.