Selective Solid-Phase Extraction of Ni(II) by an Ion-Imprinted Polymer from Biological Samples

A new ion-imprinted polymer material was synthesized by copolymerization of 2-vinylpyridine as monomer, ethyleneglycoldimethacrylate as crosslinking agent and azobisisobutyronitrile as initiator in the presence of Ni-5-(4-carboxylphenylazo)-8-hydroxyquinoline complex. The ion-imprinted polymer was used as sorbent in a solid-phase extraction column. The effects of sampling volume, elution conditions, sample pH and sample flow rate on the ion extraction of Ni ions form biological samples were studied. The maximum adsorption capacity and the relative selectivity coefficients of imprinted polymer for Ni(II)/Co(II), Ni(II)/Cu(II) and Ni(II)/Zn(II) were calculated. Compared with non-imprinted polymer particles, the ion imprinted polymer had higher selectivity for Ni(II). The detection limit for 250 mL of sample was 0.2 mu g L-1 using flame atomic absorption spectrometry. The analytical results for the certified reference samples (GBW10016) were in a good agreement with the certified value. The relative standard deviation for eleven replicate sample of 5.0 mu g L-1 level is 2.5 %. The developed method was successfully applied to the determination of trace nickel in biological samples with satisfactory results.