A facile electrochemical sensor based on amino-functionalized magnetic nanoparticles for simultaneous detection of lead and mercuric ions

The development of a facile analytical way for detecting toxic heavy metal ions is highly desirable due to their serious toxicity to human health. In this work, amino-functionalized magnetic nanoparticles (Fe3O4@SiO2-NH2) were prepared by hydrothermal and sol-gel method for electrochemical detection of lead ions (Pb2+) and mercuric ions (Hg2+). All prepared materials were characterized by four kinds of technologies. The proposed sensor was fabricated by the compound of Fe3O4@SiO2-NH2 with metal ions added to the working electrode surface. Pb2+ and Hg2+ could be easily absorbed by Fe3O4@SiO2-NH2 through coordination, and differential pulse stripping voltammetry was applied to detect Pb2+ and Hg2+ directly. Several parameters, such as deposition potential, deposition time, volume, and incubation time, were optimized to obtain better sensitivity for the electrochemical determination of Pb2+ and Hg2+. Under optimal conditions, Pb2+ and Hg2+ were detected simultaneously by the developed electrochemical sensor with detection limits of 6.06 and 9.09 nmol/L, respectively. The recoveries of Pb2+ and Hg2+ in milk ranged from 95.1% to 114%. Hence, the developed electrochemical sensor presented great potential for detecting Pb2+ and Hg2+ in milk.