A highly selective magnetic sensor with functionalized Fe/Fe3O4 nanoparticles for detection of Pb2+

A magnetic sensor for detection of Pb2+ has been developed based on Fe/Fe3O4 nanoparticles modified by 3-(3,4-dihydroxyphenyl)propionic acid (DHCA). The carboxyl groups of DHCA have a strong affinity to coordination behavior of Pb2+ thus inducing the transformation of Fe/Fe3O4 nanoparticles from a dispersed to an aggregated state with a corresponding decrease, then increase in transverse relaxation time (T2) of the surrounding water protons. Upon addition of the different concentrations of Pb2+ to an aq. solution of DHCA functionalized Fe/Fe3O4 nanoparticles (DHCA-Fe/Fe3O4 NPs) ([Fe] = 90 μmol/L), the change of T2 values display a good linear relationship with the concentration of Pb2+ from 40 μmol/L to 100 μmol/L and from 130 μmol/L to 200 μmol/L, respectively. Owing to the especially strong interaction between DHCA and Pb2+, DHCA-Fe/Fe3O4 NPs exhibited a high selectivity over other metal ions.

Graphical abstractFunctionalized Fe/Fe3O4 nanoparticles was developed to detect Pb2+.Figure optionsDownload full-size imageDownload as PowerPoint slide