Sensitive, selective and simultaneous electrochemical detection of multiple heavy metals in environment and food using a lowcost Fe3O4 nanoparticles/fluorinated multi-walled carbon nanotubes sensor.

Multiple heavy metals pollution in environment and food has become an ever-increasing concern and poses a serious threat towards humans and animals. To broad the multiple heavy metals detection, Fe3O4 nanoparticles, Fe3O4/multi-walled carbon nanotubes (Fe3O4/MWCNTs) and Fe3O4/fluorinated multi-walled carbon nanotubes (Fe3O4/F-MWCNTs) nanocomposites were synthesized by hydrothermal method and constructed as a simultaneous electrochemical sensor, respectively. Compared the catalytic performances of the three electrochemical sensors for the simultaneous detection of Cd2+, Pb2+, Cu2+, and Hg2+, the results showed that the Fe3O4/F-MWCNTs sensor demonstrated preponderant performance. It showed the sensitivity of 108.79, 125.91, 160.85, and 312.65 µA mM-1 cm-2 toward Cd2+, Pb2+, Cu2+, and Hg2+, respectively, which was obviously higher than that of Fe3O4/MWCNTs and Fe3O4. Additionally, the Fe3O4/F-MWCNTs sensor exhibited the wider linear detection ranges of 0.5-30.0, 0.5-30.0, 0.5-30.0, and 0.5-20.0 µM for Cd2+, Pb2+, Cu2+, and Hg2+, respectively. The limit of detections of the Fe3O4/F-MWCNTs sensor were 0.05, 0.08, 0.02, and 0.05 nM (signal to noise ratio of 3) for Cd2+, Pb2+, Cu2+, and Hg2+, respectively, fulfilling the governmental requests of the World Health Organization, China and Indian. The excellent agreement was recorded between the lowcost Fe3O4/F-MWCNTs sensor and typical methods (inductively coupled plasma mass spectrometry or atomic fluorescence spectrometry) in river water and soybean samples. Additionally, the sensor also exhibited excellent performances in selectivity, recovery, stability, and reproducibility. This proposal sensor provides a promising strategy to monitor multiple targets in the environment and food.