From Synthesis to Sensing: The Insight into the Properties of Fe3O4 Magnetic Nanoparticles and Their Surface Modification Strategies in Voltammetric Trace Determination of Heavy Metal Ions

Magnetic nanoparticles (MNPs) of iron oxide are becoming increasingly popular due to their excellent physicochemical properties as well as very good adsorption and catalytic properties towards heavy metal ions (HMIs). They are used in many industries and are becoming a desirable electrode material in voltammetry. Unfortunately, they tend to aggregate and easily oxidize. To mitigate these issues, they are often coated with organic or inorganic materials, which reduce oxidation and aggregation, and introduce an additional number of active sites capable of interacting with the analyte. Another approach involves the use of carbon material as a base for nanoparticles, which also improves the parameters of nanoparticles. This review reveals a condensed concept presenting functionalized Fe3O4 magnetic nanoparticles from the methods of their synthesis and modification to their application in the voltammetric trace analysis of HMIs. This paper describes the effect of electrode surface modification strategies on the stability of MNPs and the homogeneity of their distribution on the carbonaceous carrier surface. The authors focused on the voltammetric procedures for the single and simultaneous determination of HMIs using different electrode materials modified with Fe3O4 magnetic nanoparticles.