Applications of magnetic nanoparticles for the selective extraction of trace species from a complex matrix
Sample pretreatment procedures are the most important steps prior to analysis. Accuracy and reliability of results are directly affected by these steps. An ideal pretreatment procedure should be simple, cost effective, environmentally friendly, and it should be compatible with detection method. There are two fundamental goals of pretreatment procedures; separation of matrix components and pre-concentration of trace analyte species. Solid phase extraction (SPE) methods are mainly preferred owing to useful and practical properties. These methods are mainly applied as column and batch type. Application of column methods for routine analysis is mostly limited by sample volume, process time, complex structure of sample, and costs. The most important challenge in batch methods are final separation of solid phase and selectivity of solid phase for target species. Use of magnetic solids in SPE methods provides important advantages to overcome these complications. Their magnetic properties furnish an easy phase separation using a magnet, after accumulation of target molecules on particles. Moreover, the required selectivity can be obtained by covering the core with functional groups specific for analyte species. These are ideal properties expected from an effective pre-concentration and separation method. Magnetic nanoparticles have been used to pre-concentrate trace analytes and also to separate them from matrix media. Analyte species are concentrated during this process, and they can be determined by most of the conventional techniques even if they are at trace level in the original samples. Chemical synthesis of magnetite particles is well known since a long time: aqueous mixtures of Fe(II) and Fe(III) salts are mixed at room temperature in alkali medium. Then, the immediate precipitation of a black magnetic product constituted of rocklike magnetite particles, which are negatively charged and associated to the counterions of the alkali and organic and inorganic species, was obtained. They can be modified with silica supports, carbon nanotubes, alumina, and organic polymers in accordance with analyte species. Magnetic nanoparticles are used for a lot of kind of sample type: biological, environmental, plants, etc. Synthesis, characterizations, and some applications of magnetic particles as effective material will be discussed throughout this chapter. The future perspectives of magnetic solid applications will be also submitted with a few proposals. © 2017 by Nova Science Publishers, Inc.