The morphology and size of Fe3O4 nanoparticles before coating them with sodium dodecyl sulfate and diphenyl carbazone is illustrated in Fig. 1 and Fig. 2 and 2.It is necessary to investigate the effect of all the parameters that can probably influence the extraction performance. In this methodology, these parameters include the kind and amount of eluting solution, pH, amount of sorbent, and volume and concentration of ligand which were investigated and optimized in order to achieve a high recovery and enrichment factor. In all optimization steps, the concentration of cadmium was 0.5 mg L−1.