A new fibrous sorbent containing ethylenediamine, carboxyl, and tetrazine groups based on polyacrylonitrile fiber was synthesized and developed for the preconcentration of heavy metal ions. The experimental parameters such as pH value, sorptive capacity, flow velocity, reuse, as well as eluent type and concentration were investigated in detail. All the studied metal ions can be quantitatively retained by the modified fiber under pH greater than or equal to 3.5, then eluted by using a mixture of 1 mol/L hydrochloric acid and 5% thiocarbamide as eluent warmed to 40 degrees C. The column technique was applied for the concentration of Cu(II), Cd(II), Zn(II), Mn(II), Pb(II), Co(II), and Ni(II) ions in model samples with satisfactory results, and the relative standard deviations for the determination of metal ions were found to be less than 5%.