Development of a modified QuEChERS method based on magnetic multiwalled carbon nanotubes for the simultaneous determination of veterinary drugs, pesticides and mycotoxins in eggs by UPLC-MS/MS.

The growing interest in magnetic materials as a universal tool has been shown by an increasing number of scientific publications regarding magnetic materials and its various applications. Substantial progress has been recently made on the synthesis of magnetic iron oxide particles in terms of size, chemical composition, and surface chemistry. In addition, surface layers of polymers, silica, biomolecules, etc., on magnetic particles, can be modified to obtain affinity to target molecules. The developed magnetic iron oxide particles have been significantly utilized for diagnostic applications, such as sample preparations and biosensing platforms, leading to the selectivity and sensitivity against target molecules and the ease of use in the sensing systems. For the process of sample preparations, the magnetic particles do assist in target isolation from biological environments, having non-specific molecules and undesired molecules. Moreover, the magnetic particles can be easily applied for various methods of biosensing devices, such as optical, electrochemical, and magnetic phenomena-based methods, and also any methods combined with microfluidic systems. Here we review the utilization of magnetic materials in the isolation/preconcentration of various molecules and cells, and their use in various techniques for diagnostic biosensors that may greatly contribute to future innovation in point-of-care and high-throughput automation systems.

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Magnetic Particles: Their Applications from Sample Preparations to Biosensing Platforms.

Recent applications of magnetic solid phase extraction in sample preparation for phytochemical analysis.

Magnetic nanoparticles show excellent features such as small size, high surface area, active surface that can successfully be modified, low toxicity, and superparamagnetism. These unique features of magnetic nanoparticles make them excellent candidates for the design and fabrication of new functional nanomaterials for the solid-phase extraction processes. Magnetic nanoparticles are directly dispersed in the sample solutions for quick extraction of the target compound/s, as they can be readily recovered by a magnet, which overcomes drawbacks of the conventional adsorbent materials such as time consumption and large volume of samples. This chapter aims to describe and highlight the latest developments in design and preparation of novel magnetic nanoparticles. The methodologies for the synthesis of these nanoparticles, as well as their potential use in the selective extraction of the target compound/s from complex samples (i.e., environmental, biological, food and beverage samples) are demonstrated.

The use of magnetic nanoparticles in sample preparation devices and tools

Applications of surface functionalized Fe3O4 NPs-based detection methods in food safety.

A nanomaterial comprising Fe3O4-modified hydroxylated multi-walled carbon nanotubes (Fe3O4–MWCNTs–OH) was prepared by a co-precipitation method. Combined with HPLC-photodiode array detector (DAD), Fe3O4–MWCNTs–OH was used to determine brucine in human urine. Some important parameters that could influence extraction efficiency of brucine were optimized, including the extraction time, amounts of Fe3O4–MWCNTs–OH, pH of sample solutions, desorption solvent and desorption time. Under the optimal conditions, the recoveries of brucine from spiked urine samples were between 93.1 and 104.1%, and the relative standard deviations (RSDs) ranged from 3.1 to 5.7%. The correlation coefficient was 0.9997. The limits of detection and quantification were 6 and 21 ng/mL at a signal-to-noise ratio of 3 and 10, respectively. The results indicated that Fe3O4–MWCNTs–OH combined with HPLC–DAD is a promising solid-phase extraction material for the sample pretreatment in the determination of brucine.

Zufei Feng

Papers

Fast SPE and HPLC–DAD determination of brucine in human urine using multi-walled carbon nanotubes modified with magnetic nanoparticles