A solid-phase extraction procedure was described for the quantitative extraction of a mixture of lead, cadmium, copper and bismuth ions on modified multiwalled carbon nanotubes, graphene oxide nanosheets, activated carbon and carbon black, individually. Then, the adsorbed analytes were eluted with HCl and introduced directly to electrothermal atomic absorption spectrometry. The surface morphology of the adsorbents was investigated by field-emission scanning electron microscopy. The parameters affecting the adsorption–elution process such as pH and flow rate of the sample solution—type, concentration, volume and flow rate of eluent were optimized in detail. Adsorption capacities, breakthrough volumes and enrichment factors were also studied. Wide calibration curves with good correlation coefficients, low detection limits and acceptable relative standard deviations were obtained for all analytes on different adsorbents. The results showed, when nanoadsorbents were used, higher adsorption and recoveries were obtained for all of the studied metal ions. The proposed method has been applied to the determination of Pb(II), Cd(II), Cu(II) and Bi(III) in water, wastewaters, human urine and human hair samples. The spiked recoveries were in the range 93.0–106%. Also, the accuracy of the method was validated by analyzing a certified reference material.