Extraction Methods Facilitated by the use of Magnetic Nanoparticles

Abstract

Magnetic nanoparticles (MNPs) are a group of nanoparticles (NPs) that present superparamagnetic properties. MNPs are composed of a magnetic solid phase that is responsible for the magnetic properties. The characterization of MNPs is usually accomplished using techniques such as X‐ray diffraction (XRD), transmission electron microscopy (TEM), or scanning electron microscopy (SEM). Several review articles have been recently devoted to MNPs in analytical chemistry and particularly to sample preparation. This chapter presents extraction methods facilitated by the use of MNPs, with particular emphasis on MNP types and extraction applications. The relatively simple tuneability of MNPs, by easily anchoring task‐specific sorbents of quite different nature (silica based, carbon and derivatives based, polymeric based, and so on), opens a number of possible combinations and enormously extends its future applications

Role of Ionic Liquids in Composites in Analytical Sample Preparation

“…Magnetic particles (MPs) are a group of particles widely employed in analytical sample preparation characterized for exhibiting magnetic properties. They are mostly made from transition metals like iron (Fe), cobalt (Co) and nickel (Ni), or from their oxides and sulfides, such as cobalt ferrite (CoFe 2 O 4 ), magnetite (α-Fe 3 O 4 ), and greigite (Fe 3 S 4 ) [23,28,29]. These materials can be synthesized by different methods, being the microwave-assisted method, the solvothermal preparation, and the chemical co-precipitation of two inorganic salts in basic medium, the most well-known and applied approaches [30][31][32].…”

“…With the aim of overcoming these drawbacks, magnetic-based extraction sorbents are prepared (and indeed widely explored) by the modification of bare MPs, mainly by their surface functionalization or by their protection with a coating formed using another material [29][30][31]35,36]. Among the materials used for their modification and preparation of magnetic composites, ILs and their derivatives merit to be highlighted [23].…”

Magnetic ionic liquids as non-conventional extraction solvents for the determination of polycyclic aromatic hydrocarbons

“…Magnet-based separations constitute a quite interesting and evolvingadvancement in sample preparation [20]. These methods utilize an extractant material with magnetic properties.…”

“…in a number of magnet-based extraction approaches.Bare Fe 3 O 4 MNPs tend to aggregate, they easily oxidize in air, or they experience biodegradation, and thus coatings are required in an attempt to increase their stability [20]. Applications using Fe 3 O 4 @ILs (or @IL-based surfactants) require more than one synthetic step (that of the IL and that of the Fe 3 O 4 magnetic nanoparticles, MNPs); and in some cases the whole extraction efficiency of the hybrid material is lower than that of the neat IL (or IL-based surfactant).…”

“…Applications using Fe 3 O 4 @ILs (or @IL-based surfactants) require more than one synthetic step (that of the IL and that of the Fe 3 O 4 magnetic nanoparticles, MNPs); and in some cases the whole extraction efficiency of the hybrid material is lower than that of the neat IL (or IL-based surfactant). In some approaches, dispersive solvents or agitation may be needed to disperse the extractionphase and improve the mass transfer of the analytes to the microamounts of material [20].…”