Polyethyleneimine-modified magnetic carbon nanotubes as solid-phase extraction adsorbent for the analysis of multi-class mycotoxins in milk via liquid chromatography-tandem mass spectrometry

Modification of hollow microporous organic network with polyethyleneimine for efficient enrichment of phenolic acids from fruit juice samples

Owning to the hydrophobic characteristics of microporous organic networks (MONs), their utilizations still largely limited in non- and weak-polar analytes. To expend their applications, here we reported the synthesis of a novel hollowed H-MON-PEI1800-2 composite via sacrifice template method and subsequent modification with polyethyleneimine (PEI) for efficient solid phase extraction of polar and ionic phenolic acid (PAs) from fruit juice samples. H-MON-PEI1800-2 exhibits large surface area, rapid extraction kinetics, remarkable chemical and thermal stabilities, and provides synergistic electrostatic, π-π, hydrogen bonding, and hydrophobic interaction sites for PAs. The developed method owns low limit of detection, wide linear range, large enrichment factors, and good reusability. The recoveries of H-MON-PEI1800-2 for PAs are 1-3 orders of magnitude higher than those of commercial adsorbents like activated carbon, C18 and Oasis HLB. This work highlights the prospects of functional H-MONs for enriching polar and ionic targets from complex sample matrices.

Polyethyleneimine in designed nanocomposite based magnetic halloysite nanotubes for extraction and determination of gallic acid in green tea

An innovative and simple nanocomposite denoted as MHNTs@PEI was synthesized for gallic acid (GA) analytical sample pretreatment. Polyethyleneimine (PEI) functionalized was binded onto magnetic halloysite nanotubes (MHNTs) to inhence adsorption capacity. MHNTs@PEI was obtained only through two steps modification (amination and PEI modification). Characterizations showed that there are layers of synthetic PEI on the tubular structure of the material and magnetic spheres on its surface, both indicating successful synthesis of the nanocomposite. Furthermore, the adsorption isotherms and kinetic modeling showed that the Langmuir model and pseudo-first-order model fit the adsorption data, respectively. MHNTs@PEI achieved an adsorption capacity of 158 mg·g-1. Overall, the abundant adsorption sites significantly improved the adsorption performance of the MHNTs@PEI. Regeneration tests demonstrated that the MHNTs@PEI exhibits effective adsorption, even after undergoing five consecutive cycles. Optimization of key parameters (ratio, volume of elution, elution time and frequency) in the process of adsorption and desorption was also conducted. The limit of detection (LOD) and that of the quantification (LOQ) were 0.19 and 0.63 μg·mL-1, respectively, and the recoveries were 95.67-99.43 %. Finally, the excellent magnetism (43.5 emu·g-1) and the adsorption feature of MHNTs@PEI enabled its successful utilization in analytical sample pretreatment through the extraction of GA from green tea.

Magnetic nanoparticle-based immunosensors and aptasensors for mycotoxin detection in foodstuffs: An update

Mycotoxin contamination of food crops is a global challenge due to their unpredictable occurrence and severe adverse health effects on humans. Therefore, it is of great importance to develop effective tools to prevent the accumulation of mycotoxins through the food chain. The use of magnetic nanoparticle (MNP)-assisted biosensors for detecting mycotoxin in complex foodstuffs has garnered great interest due to the significantly enhanced sensitivity and accuracy. Within such a context, this review includes the fundamentals and recent advances (2020-2023) in the area of mycotoxin monitoring in food matrices using MNP-based aptasensors and immunosensors. In this review, we start by providing a comprehensive introduction to the design of immunosensors (natural antibody or nanobody, random or site-oriented immobilization) and aptasensors (techniques for aptamer selection, characterization, and truncation). Meanwhile, special attention is paid to the multifunctionalities of MNPs (recoverable adsorbent, versatile carrier, and signal indicator) in preparing mycotoxin-specific biosensors. Further, the contribution of MNPs to the multiplexing determination of various mycotoxins is summarized. Finally, challenges and future perspectives for the practical applications of MNP-assisted biosensors are also discussed. The progress and updates of MNP-based biosensors shown in this review are expected to offer readers valuable insights about the design of MNP-based tools for the effective detection of mycotoxins in practical applications.

Recent advances in simultaneous detection strategies for multi-mycotoxins in foods

Mycotoxin contamination has become a challenge in the field of food safety testing, given the increasing emphasis on food safety in recent years. Mycotoxins are widely distributed, in heavily polluted areas. Food contamination with these toxins is difficult to prevent and control. Mycotoxins, as are small-molecule toxic metabolites produced by several species belonging to the genera Aspergillus, Fusarium, and Penicillium growing in food. They are considered teratogenic, carcinogenic, and mutagenic to humans and animals. Food systems are often simultaneously contaminated with multiple mycotoxins. Due to the additive or synergistic toxicological effects caused by the co-existence of multiple mycotoxins, their individual detection requires reliable, accurate, and high-throughput techniques. Currently available, methods for the detection of multiple mycotoxins are mainly based on chromatography, spectroscopy (colorimetry, fluorescence, and surface-enhanced Raman scattering), and electrochemistry. This review provides a comprehensive overview of advances in the multiple detection methods of mycotoxins during the recent 5 years. The principles and features of these techniques are described. The practical applications and challenges associated with assays for multiple detection methods of mycotoxins are summarized. The potential for future development and application is discussed in an effort, to provide standards of references for further research.

Hydrophilic Covalent Organic Frameworks Coated Steel Sheet As a Mass Spectrometric Ionization Source for the Direct Determination of Zearalenone and Its Derivatives

Zearalenone has attracted worldwide attention due to its toxic properties and threat to public health. A rapid determination method for zearalenone and its derivatives by hydrophilic covalent organic frameworks coated steel sheet (HCOFCS) combined with ambient mass spectrometry (AMS) was developed. The HCOFCS behaved as both a tip for solid-phase microextraction and a solid substrate for electrospray ionization mass spectrometry (ESI-MS). To evaluate the HCOFCS-ESI-MS method, five zearalenone and its derivatives in milk samples were determined, including zearalenone (ZEA), α-zearalenol (α-ZEL), β-zearalenol (β-ZEL), α-zearalanol (α-ZAL), and β-zearalanol (β-ZAL). After the extraction procedure, the HCOFCS was directly added with a high voltage for ESI-MS, and the analysis could be completed within 1 min. The developed method showed good linearity in the range 0.1-100 μg/L with a coefficient of determination (R²) > 0.9991. The limits of detection (LODs) and limits of quantitation (LOQs) ranged from 0.05 to 0.1 and 0.2 to 0.3 μg/L, respectively. The results demonstrated that the HCOFCS combined with ESI-MS can be used for the rapid and sensitive determination of trace ZEA and its derivatives in milk samples with satisfactory recoveries from 80.58% to 109.98% and reproducibility with relative standard deviations (RSDs) no more than 11.18%. Furthermore, HCOFCS showed good reusability, which could reuse at least 10 extraction cycles with satisfactory adsorption performance.

Fe3O4@PDA/MIL-101(Cr) as magnetic solid-phase extraction sorbent for mycotoxins in licorice prior to ultrahigh-performance liquid chromatography-tandem mass spectrometry analysis

Magnetic solid-phase extraction (MSPE) strategy based on the Fe3O4@PDA/MIL-101(Cr) has been proposed to separate and purify five common mycotoxins in licorice, including aflatoxin B1, aflatoxin G1, sterigmatocystin, zearalenone, and ochratoxin A. Integrating the MSPE and solid-liquid extraction/partitioning, a modified QuEChERS was established to adapt to the complex licorice samples. The Fe3O4@PDA/MIL-101(Cr) was successfully synthesized and characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen adsorption-desorption isotherms. Sorbents with superior advantages for exclusion of matrix interference and extraction of target analytes in a short time were obtained, according to their ability of magnetic separation, high surface area (287.75 m2/g), large pore volume (0.61 cm3/g), and nanosized structure with mesopores. Prior to analysis with ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), several key parameters that would affect the sorbents' extraction efficiency were extensively investigated. Under the optimized conditions, the practicality of the developed method for analysis of mycotoxins in licorice samples was confirmed by adequate linearity (R 2 ≥ 0.9967), high sensitivity (LODs and LOQs, respectively, in the ranges 0.01-0.09 and 0.02-0.30 μg/kg), acceptable recovery (78.53%-116.28%), satisfactory reusability, and good interbatch precision of the sorbents (RSDs in the ranges 6.70%-11.20% and 6.02%-10.35%, respectively). The results indicated that the established method was feasible and reliable for the environment-friendly and rapid screening of mycotoxins in complex licorice samples.

Effective removal of Pb(II) ions using piperazine-modified magnetic graphene oxide nanocomposite; optimization by response surface methodology

In this research, the piperazine-modified magnetic graphene oxide (Pip@MGO) nanocomposite was synthesized and utilized as a nano-adsorbent for the removal of Pb(II) ions from environmental water and wastewater samples. The physicochemical properties of Pip@MGO nanocomposite was characterized by X-ray diffraction analysis (XRD), Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDAX), Thermo-gravimetric analysis (TGA), Vibrating Sample Magnetometery (VSM) and Fourier-transform infrared spectroscopy (FT-IR) analysis. In this method, the batch removal process were designed by response surface methodology (RSM) based on a central composite design (CCD) model. The results indicated that the highest efficiency of Pb(II) removal was obtained from the quadratic model under optimum conditions of prominent parameters (initial pH 6.0, adsorbent dosage 7 mg, initial concentration of lead 15 mg L⁻¹ and contact time 27.5 min). Adsorption data showed that lead ions uptake on Pip@MGO nanocomposite followed the Langmuir isotherm model equation and pseudo-second order kinetic model. High adsorption capacity (558.2 mg g⁻¹) and easy magnetic separation capability showed that the synthesized Pip@MGO nanocomposite has great potential for the removal of Pb(II) ions from contaminated wastewaters.

Solid-phase extraction techniques based on nanomaterials for mycotoxin analysis: An overview for food and agricultural products

Mycotoxin contamination is a globally concerned problem for food and agricultural products since it may directly or indirectly induce severe threats to human health. Sensitive and selective screening is an efficient strategy to prevent or reduce human and animal exposure to mycotoxins. However, enormous challenges exist in the determination of mycotoxins, arising from complex sample matrices, trace-level analytes, and the co-occurrence of diverse mycotoxins. Appropriate sample preparation is essential to isolate, purify, and enrich mycotoxins from complicated matrices, thus decreasing sample matrix effects and lowering detection limits. With the cross-disciplinary development, new solid-phase extraction strategies have been exploited and integrated with nanotechnology to meet the challenges of mycotoxin analysis. This review summarizes the advance and progress of solid-phase extraction techniques as the methodological solutions for mycotoxin analysis. Emphases are paid on nanomaterials fabricated as trapping media of SPE techniques, including carbonaceous nanoparticles, metal/metal oxide-based nanoparticles, and nanoporous materials. Advantages and limitations are discussed, along with the potential prospects. This article is protected by copyright. All rights reserved.

Simultaneous Determination of 23 Mycotoxins in Broiler Tissues by Solid Phase Extraction UHPLC-Q/Orbitrap High Resolution Mass Spectrometry

Mycotoxins are a type of toxins harmful for not only animal but also human health. Cooccurrence of multi-mycotoxins could occur for food infected by several molds, producing multi-mycotoxins. It is necessary to develop corresponding determination methods, among which current mass spectrometry (MS) dominates. Currently, the accurate identification and quantitation of mycotoxins in complex matrices by MS with low resolution is still a challenge since false-positive results are typically obtained. Here, a method for the simultaneous determination of 23 mycotoxins in broiler tissues using ultra-high performance liquid chromatography-quadrupole/orbitrap HRMS was established. After the extraction by acetonitrile-water-formic acid (80:18:2, v/v/v), the purification by multifunctional purification solid phase extraction cartridges and the chromatographic separation on a C18 column, representative mycotoxins were determined by HRMS in full scan/data-dependent MS/MS acquisition mode. The quantitation was based on the external standard method. An MS/MS database of 23 mycotoxins was established to achieve qualitative screening and simultaneous quantification. Mycotoxins had a good linear relationship within a certain concentration range with correlation coefficients (r2) larger than 0.991 as well as the limit of quantitation of 1.80–300 μg/kg. The average recoveries at three different levels of low, medium and high fortification were 61–111% with relative standard deviations less than 13.5%. The method was fast, accurate, and suitable for the precise qualification of multiple mycotoxins in broiler tissues. 15 μg/kg zearalenone (ZEN) was detected in one liver sample among 30 samples from markets including chicken breast meat, liver, and gizzards. The result illustrated that the pollution of ZEN should not be neglected considering its harmful effect on the target organ of liver.

Qualitative-quantitative analysis of multi-mycotoxin in milk using the high-performance liquid chromatography-tandem mass spectrometry coupled with the quick, easy, cheap, effective, rugged and safe method

High-performance liquid chromatography-tandem mass spectrometry coupled with the quick, easy, cheap, effective, rugged and safe method was established for the qualitative and quantitative detections of 20 mycotoxins in milk. The linear range of this method was 0.01-10 μg/L and the correlation coefficients were all greater than or equal to 0.9933. At three levels of addition, the spiked recoveries ranged from 80.00 to 112.50%, relative standard deviations were 2.67-14.97%, limits of quantitation were 0.02-4.00 μg/kg, and limits of detection were 0.007-1.300 μg/kg. This developed procedure for the identification and quantitation of mycotoxins provided prospective support for quality regulation.

A Review of the Use of Carbon Nanotubes and Graphene-Based Sensors for the Detection of Aflatoxin M1 Compounds in Milk

This paper presents a comprehensive review of the detection of aflatoxin compounds using carbon allotrope-based sensors. Although aflatoxin M1 and its derivative aflatoxin B1 compounds have been primarily found in milk and other food products, their presence above a threshold concentration causes disastrous health-related anomalies in human beings, such as growth impairment, underweight and even carcinogenic and immunosuppressive effects. Among the many sensors developed to detect the presence of these compounds, the employment of certain carbon allotropes, such as carbon nanotubes (CNTs) and graphene, has been highly preferred due to their enhanced electromechanical properties. These conductive nanomaterials have shown excellent quantitative performance in terms of sensitivity and selectivity for the chosen aflatoxin compounds. This paper elucidates some of the significant examples of the CNTs and graphene-based sensors measuring Aflatoxin M1 (ATM1) and Aflatoxin B1 (AFB1) compounds at low concentrations. The fabrication technique and performance of each of the sensors are shown here, as well as some of the challenges existing with the current sensors.