Recent Applications of Carbonaceous Nanosorbents in Solid Phase Extraction for the Determination of Pesticides in Food Samples

Stirred discs from polycaprolactone nanofibers highly doped with graphene for straightforward preconcentration of pollutants in environmental waters

A novel sorbent for solid phase extraction (SPE) based on hybrid nanofibrous polycaprolactone containing graphene nanoparticles has been prepared. The preparation of hybrid polymer nanofibers with a very high 1:1 polymer/graphene ratio was achieved for the first time using alternating current electrospinning. The final appearance of these nanofibers was a thick porous layer that was cut into the shape of easy-to-handle extraction discs. Based on the preliminary study in which the graphene content varied, 30% graphene-doped nanofibers (w/w) exhibited the highest recoveries and enabled a significant increase in the retention of analytes, 2-25 times in comparison to PCL. The incorporation of graphene resulted in a higher surface area of 12 g/m2 compared to 2 g/m2 determined for the native polycaprolactone (PCL) nanofibers. This unique material was applied for a simple stirred disc sorptive extraction and preconcentration of trace levels of emerging organic environmental contaminants, bisphenols A, AF, AP, C, S, Z, 3-chlorophenol, and pesticides fenoxycarb, deltamethrin, and kadethrin from surface waters prior to HPLC-DAD determination. This was accomplished by stirring the unsupported nanofiber disc in a large-volume sample with RSD of five extractions of 3-15%. Recoveries yielded 87-120%, except 52% for bisphenol S due to its high polarity. Optimization of the extraction procedure included conditioning, sample volume, extraction time, and elution solvent. Our novel desorption procedure carried out in a vial used for the direct injection into the HPLC system significantly reduced sample handling and minimized potential human error.

Nanoscale Materials Applying for the Detection of Mycotoxins in Foods

Trace amounts of mycotoxins in food matrices have caused a very serious problem of food safety and have attracted widespread attention. Developing accurate, sensitive, rapid mycotoxin detection and control strategies adapted to the complex matrices of food is crucial for in safeguarding public health. With the continuous development of nanotechnology and materials science, various nanoscale materials have been developed for the purification of complex food matrices or for providing response signals to achieve the accurate and rapid detection of various mycotoxins in food products. This article reviews and summarizes recent research (from 2018 to 2023) on new strategies and methods for the accurate or rapid detection of mold toxins in food samples using nanoscale materials. It places particular emphasis on outlining the characteristics of various nanoscale or nanostructural materials and their roles in the process of detecting mycotoxins. The aim of this paper is to promote the in-depth research and application of various nanoscale or structured materials and to provide guidance and reference for the development of strategies for the detection and control of mycotoxin contamination in complex matrices of food.

Recent Applications of Magnetic Nanoparticles in Food Analysis

Nanotechnology has become a topic of interest due to the outstanding advantages that the use of nanomaterials offers in many fields. Among them, magnetic nanoparticles (m-NPs) have been one of the most widely applied in recent years. In addition to the unique features of nanomaterials in general, which exclusively appear at nanoscale, these present magnetic or paramagnetic properties that result of great interest in many applications. In particular, in the area of food analysis, the use of these nanomaterials has undergone a considerable increase since they can be easily separated from the matrix in sorbent-based extractions, providing a considerable simplification of the procedures. This allows reducing cost and giving fast responses, which is essential in the food trade to guarantee consumer safety. These materials can also be easily tunable, providing higher selectivity. Moreover, their particular electrical, thermal and optical characteristics allow enhancing sensor signals, increasing the sensitivity of the approaches based on this type of device. The aim of this review article is to summarise the most remarkable applications of m-NPs in food analysis in the last five years (2016–2020) showing a general view of the use of such materials in the field.

A poly(N,N-dimethylaminoethyl methacrylate-co-ethylene glycol dimethacrylate) monolith for direct solid-phase extraction of benzodiazepines from undiluted human urine

A novel polymeric monolith using N,N-dimethylaminoethyl methacrylate as the monomer and ethylene glycol dimethacrylate as the crosslinker was successfully synthesized in a syringe and applied for direct solid-phase extraction of four benzodiazepines (bromazepam, triazolam, midazolam and diazepam) from undiluted urine samples prior to high performance liquid chromatography. The monolith was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and nitrogen adsorption-desorption experiments. Moreover, extraction parameters, including loading, washing and eluting conditions were optimized. Under the optimized conditions, the proposed method obtained linear ranges of 2.0-500 ng mL^-1 with correlation coefficients (r) higher than 0.9997. The limits of detection (S/N = 3) and limits of quantification (S/N = 10) were 0.4-0.6 ng mL^-1 and 1.4-2.0 ng mL^-1, respectively. The recoveries at three spiked levels ranged from 83.7% to 103% with the intra- and inter-day precisions from 0.6-7.6% to 2.7-9.8%. The present monolith allowed direct loading of crude urine samples without any filtration or dilution step. Besides, the sorbent offered an enhancement factor of 16.7-20.6 and was stable enough for ten replicate cycles of extraction/desorption of urine samples. The developed method presented an alternative strategy for the accurate and convenient determination of benzodiazepines in urine samples.

Use of Nanomaterial-Based (Micro)Extraction Techniques for the Determination of Cosmetic-Related Compounds

The high consumer demand for cosmetic products has caused the authorities and the industry to require rigorous analytical controls to assure their safety and efficacy. Thus, the determination of prohibited compounds that could be present at trace level due to unintended causes is increasingly important. Furthermore, some cosmetic ingredients can be percutaneously absorbed, further metabolized and eventually excreted or bioaccumulated. Either the parent compound and/or their metabolites can cause adverse health effects even at trace level. Moreover, due to the increasing use of cosmetics, some of their ingredients have reached the environment, where they are accumulated causing harmful effects in the flora and fauna at trace levels. To this regard, the development of sensitive analytical methods to determine these cosmetic-related compounds either for cosmetic control, for percutaneous absorption studies or for environmental surveillance monitoring is of high interest. In this sense, (micro)extraction techniques based on nanomaterials as extraction phase have attracted attention during the last years, since they allow to reach the desired selectivity. The aim of this review is to provide a compilation of those nanomaterial-based (micro)extraction techniques for the determination of cosmetic-related compounds in cosmetic, biological and/or environmental samples spanning from the first attempt in 2010 to the present.

Preparation of levofloxacin-imprinted nanoparticles using designed deep eutectic solvents for the selective removal of levofloxacin pollutants from environmental waste water

Designed deep eutectic solvents was applied to preparation of levofloxacin-imprinted nanoparticles as functional monomer. The nanoparticles using for the selective removal of levofloxacin pollutants from a natural environmental system.

Modified QuEChERS Extraction and HPLC-MS/MS for Simultaneous Determination of 155 Pesticide Residues in Rice (Oryza sativa L.)

Rice (Oryza sativa L.) is the staple food of more than half of the world’s population. The main factors affecting the quality of rice include grain length, texture, stickiness, flavor, and aroma. Pesticides are intended for the protection of plant products from weeds, fungi, or insects. However, pesticides also result in negative effects such as environment disturbances, pest resistance and toxicity to both users and food consumers. The aim of this study was to conduct validation experiments of a method for the determination of multi-pesticides in rice, a model food of other cereals. A quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was used for the extraction of pesticide residues from rice followed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) with a triple quadrupole instrument using electrospray ionization. The analytical method has chromatography-tandem according to SANTE/11813/2017. The limit of quantification was 5 μg/kg. Recoveries for the 155 analyzed pesticides ranged between 77.1% for pirimiphos-ethyl and 111.5% for flutriafol and they were determined at 3 spiking levels. The proposed method was demonstrated to be quick, simple, precise, and accurate and allowed for evaluating the compliance of cereals samples with legislated maximum residue levels of pesticides in the European Union.