In this work, a solid phase extraction method for selective separation and column preconcentration of ultra trace amounts of Zn(II) on modified multiwalled carbon nanotubes (MMWNTs) prior to its flame atomic absorption spectrometric determinations has been investigated. Multiwalled carbon nanotubes (MWCNTs) were oxidized and modified, and were then used as a solid phase for the column preconcentration of zinc ion. The influences of some analytical parameters (including pH of the solution, flow rate of sample and eluent, type and concentration of eluent, sample volume and interfering ions) were investigated for optimization of the presented procedure. Quantitative recovery of Zn(II) was achieved by stripping with 0.5 mol L-1 HNO3. A preconcentration factor of 250 was achieved in this method. In the initial solution, the detection limit for Zn(II) was found as 0.07 pg mL(-1). Also, the relative standard deviation was +/- 1.20% (n=8 and C=1.0 ng mL(-1)). The validation of the procedure was performed by the analysis of the certified standard reference materials, and the presented procedure was applied to the determination of analytes in biological and water samples with good results. (C) 2011 Elsevier B.V. All rights reserved.