Fluorine and nitrogen functionalized magnetic graphene as a novel adsorbent for extraction of perfluoroalkyl and polyfluoroalkyl substances from water and functional beverages followed by HPLC-Orbitrap HRMS determination

Rapidly enrichment and detection of per-and polyfluoroalkyl substances in foods using a novel bifunctional covalent organic framework

Per- and polyfluoroalkyl substances (PFASs) are extensively found in foods, posing potential toxicity to humans. Therefore, rapid analysis and monitoring of PFASs in foods are crucial for public health and also a challenge. To detect trace PFASs in foods, construction of sorbents with multiple interactions could be an effective approach. Herein, a cationic-fluorinated covalent organic framework (CF-COF) was prepared by post-modification and used as a magnetic solid-phase extraction adsorbent for adsorption of PFASs. By combining magnetic solid-phase extraction based on CF-COF with liquid chromatography-tandem mass spectrometry (LC - MS/MS), a novel method was developed for determination of eight long-chain PFASs in foods. Under optimized conditions, the method exhibited low detection limits (0.003-0.019 ng/g) and satisfactory recovery rates (73.5-118%) for PFASs. This study introduces a novel idea for the development of adsorbents targeting PFASs, along with a new analytical method for monitoring of PFASs in foods.

Fluorine-functionalized magnetic amino microporous organic network for enrichment of perfluoroalkyl substances

Perfluoroalkyl substances (PFAS) are persistent organic pollutants that pose significant risks to human health and the environment. Efficient and selective enrichment of these compounds was crucial for their accurate detection and quantification in complex matrices. Herein, we report a novel magnetic solid-phase extraction (MSPE) method using fluorine-functionalized magnetic amino-microporous organic network (Fe3O4@MONNH2@F7) adsorbent for the efficient enrichment of PFAS from aqueous samples. The core-shell Fe3O4@MONNH2@F7 nanosphere was synthesized, featuring magnetic Fe3O4 nanoparticles as the core and a porous amino-functionalized MONs coating as the shell, which was further modified by fluorination. The synthesized adsorbent material exhibited high specific surface area, hydrophobicity, and abundant fluorine groups, facilitating efficient and selective adsorption of PFAS via electrostatic attraction, hydrophobic-hydrophobic interactions, fluorine-fluorine interactions, π-CF interactions and hydrogen bonding. Furthermore, the MSPE method coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) allowed for the rapid, sensitive, and accurate determination of ultra-trace PFAS in real water samples, human serum, and human follicular fluid. Under optimal conditions, the established MSPE method demonstrated a linear range (2 to 2000 ng L-1), with a correlation coefficient exceeding 0.9977, low limits of detection ranging from 0.54 to 1.47 ng L-1, with a relative standard deviation (RSD) < 9.1%. Additionally, the method showed excellent performance in complex real samples (recovery ratio of 81.7 to 121.6 %). The adsorption mechanism was investigated through kinetic, isotherm, and molecular simulation studies, revealing that the introduction of fluorine groups enhanced the hydrophobic interaction and fluorine-fluorine attraction between the adsorbent and PFAS. This work provides a proof-of-concept strategy for designing adsorbent materials with high efficiency and selectivity by post-modification, which has great potential for the detection and analysis of PFAS in complex samples.

There's Something in What We Eat: An Overview on the Extraction Techniques and Chromatographic Analysis for PFAS Identification in Agri-Food Products

Per- and polyfluorinated alkyl substances (PFASs) are a group of anthropogenic chemicals used in a range of industrial processes and consumer products. Recently, their ubiquitous presence in the environment as well as their toxicological effects in humans have gained relevant attention. Although the occurrence of PFASs is widely investigated in scientific community, the standardization of analytical method for all matrices still remains an important issue. In this review, we discussed extraction and detection methods in depth to evaluate the best procedures of PFAS identification in terms of analytical parameters (e.g., limits of detection (LODs), limits of quantification (LOQs), recoveries). Extraction approaches based on liquid-liquid extraction (LLE), alkaline digestion, and solid phase extraction (SPE), followed by liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) analysis are the main analytical methods applied in the literature. The results showed detectable recoveries of PFOA and PFOS in meat, milk, vegetables, eggs products (90.6-101.2% and of 89.2-98.4%), and fish (96-108%). Furthermore, the low LOD and LOQ values obtained for meat (0.00592-0.01907 ng g-1; 0.050 ng g-1), milk (0.003-0.009 ng g-1; 0.010-0.027 ng g-1), fruit (0.002-0.009 ng g-1; 0.006-0.024 ng g-1), and fish (0.00369-0.017.33 ng g-1; 0.05 ng g-1) also confirmed the effectiveness of the recent quick, easy, cheap, effective, rugged, and safe method (QuEChERS) for simple, speedy, and sensitive ultra-trace PFAS analysis.

Recent advances in the application of magnetic materials for the management of perfluoroalkyl substances in aqueous phases

Perfluoroalkyl substances (PFASs) are a class of artificially synthesised organic compounds extensively used in both industrial and consumer products owing to their unique characteristics. However, their persistence in the environment and potential risk to health have raised serious global concerns. Therefore, developing effective techniques to identify, eliminate, and degrade these pollutants in water are crucial. Owing to their high surface area, magnetic responsiveness, redox sensitivity, and ease of separation, magnetic materials have been considered for the treatment of PFASs from water in recent years. This review provides a comprehensive overview of the recent use of magnetic materials for the detection, removal, and degradation of PFASs in aqueous solutions. First, the use of magnetic materials for sensitive and precise detection of PFASs is addressed. Second, the adsorption of PFASs using magnetic materials is discussed. Several magnetic materials, including iron oxides, ferrites, and magnetic carbon composites, have been explored as efficient adsorbents for PFASs removal from water. Surface modification, functionalization, and composite fabrication have been employed to improve the adsorption effectiveness and selectivity of magnetic materials for PFASs. The final section of this review focuses on the advanced oxidation for PFASs using magnetic materials. This review suggests that magnetic materials have demonstrated considerable potential for use in various environmental remediation applications, as well as in the treatment of PFASs-contaminated water.

An overview on human exposure, toxicity, solid-phase microextraction and adsorptive removal of perfluoroalkyl carboxylic acids (PFCAs) from water matrices

Perfluoroalkyl carboxylic acids (PFCAs) are sub-class of perfluoroalkyl substances commonly detected in water matrices. They are persistent in the environment, hence highly toxic to living organisms. Their occurrence at trace amount, complex nature and prone to matrix interference make their extraction and detection a challenge. This study consolidates current advancements in solid-phase extraction (SPE) techniques for the trace-level analysis of PFCAs from water matrices. The advantages of the methods in terms of ease of applications, low-cost, robustness, low solvents consumption, high pre-concentration factors, better extraction efficiency, good selectivity and recovery of the analytes have been emphasized. The article also demonstrated effectiveness of some porous materials for the adsorptive removal of the PFCAs from the water matrices. Mechanisms of the SPE/adsorption techniques have been discussed. The success and limitations of the processes have been elucidated.

Design of experiments (DoE) to develop and to optimize extraction of psychoactive substances

The design of experiments (DoE) method was employed to optimize the adsorption processes of seven psychoactive substances in magnetic solid phase extraction. Fe₃O₄/GO/ZIF-8 was utilized as an adsorbent for the efficient extraction of psychoactive substances from environmental water samples. The analytes were ephedrine, methylephedrine, amphetamine, methamphetamine, morphine, papaverine, and thebaine, which were determined by ultrahigh performance liquid chromatography-tandem mass spectrometry. Plackett-Burman design was employed to identify the significant factors responsible for adsorption, and Box-Behnken design was used for further optimization to obtain the optimum values for each variable. The predicted and experimental values were found to be in good agreement. The coefficient of determination (R²) values of 0.9500-0.9976 indicated that the model was significant. The linear ranges were 1-100 ng mL^-1, and the correlation coefficient was good (r² ≥ 0.995). The EF with values of about 2.5 was obtained with recoveries in the range of 74.92-94.47%. The limits of detection (LOD) and limits of quantification (LOQ) were 0.086-0.353 ng mL^-1 and 0.286-1.175 ng mL^-1, respectively. The intra-day and inter-day RSDs were in the range of 0.17-1.87% and 0.06-2.21%, respectively. By using the DoE method, the errors associated with inferring the influence and interaction between various factors can be reduced. The combination of MSPE and DoE improves the recovery, precision, and simultaneous detectability of the target analytes. It has a high potential for psychoactive substance analysis in environmental water.

Simultaneous determination of twelve mycotoxins in edible oil, soy sauce and bean sauce by PRiME HLB solid phase extraction combined with HPLC-Orbitrap HRMS

A solid phase extraction-high-performance liquid chromatography-tandem Orbitrap high resolution mass spectrometry (HPLC-Orbitrap HRMS) method was established for the determination of 12 mycotoxins (ochratoxin A, ochratoxin B, aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, HT-2 toxin, sterigmatocystin, diacetoxysciroenol, penicillic acid, mycophenolic acid, and citreoviridin) in edible oil, soy sauce, and bean sauce. Samples were extracted by 80:20 (v:v) acetonitrile-water solution, purified by PRiME HLB column, separated by aQ C18 column with mobile phase consisting of 0.5 mmol/L ammonium acetate-0.1% formic acid aqueous solution and methanol. The results showed that the limits of detection (LODs) and limits of quantification (LOQs) of 12 mycotoxins were 0.12–1.2 μg/L and 0.40–4.0 μg/L, respectively. The determination coefficients of 12 mycotoxins in the range of 0.20–100 μg/L were &gt; 0.998. The average recoveries in soy sauce and bean sauce were 78.4–106.8%, and the relative standard deviations (RSDs) were 1.2–9.7% under three levels, including LOQ, 2× LOQ and 10 × LOQ. The average recoveries in edible oil were 78.3–115.6%, and the precision RSD (n = 6) was 0.9–8.6%. A total of 24 edible oils, soy sauce and bean sauce samples were analyzed by this method. AFB1, AFB2, sterigmatocystin and mycophenolic acid were detected in several samples at concentrations ranging from 1.0 to 22.1 μg/kg. The method is simple, sensitive, and rapid and can be used for screening and quantitative analysis of mycotoxin contamination in edible oil, soy sauce, and bean sauce.

Electrospun UiO-66-F4/polyacrylonitrile nanofibers for efficient extraction of perfluoroalkyl and polyfluoroalkyl substances in environmental media

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are a family of emerging contaminants which are widely present in environment. In this work, novel UiO-66-F₄/polyacrylonitrile (UiO-66-F₄/PAN) hybrid nanofibers were firstly prepared via blend electrospinning or in-situ growth method for the pipette-tip solid phase extraction of PFASs. Characterizations demonstrate the as-synthesized UiO-66-F₄/PAN nanofibers have good chemical and thermal stability, possess large surface area (248 m²/g) and mesoporous framework structure. Several extraction factors including the amount of adsorbent, pH and ionic strength of sample solution, extraction time and eluent were investigated and the optimum conditions are 20 mg of the selected sorbent, adjusting to pH 5 and adding 4% w/v NaCl to sample solution, extraction for 12 min (3 min × 4). The good adsorption affinity of UiO-66-F₄/PAN for PFASs can be attributed to the extensive adsorption sites and multiple interactions including hydrophobic interaction, hydrogen bonding and F-F interaction. Low limit of detection (0.008-0.076 µg/L), limit of quantification (0.010-0.163 µg/L) and recoveries (70.84-113.57%) for 9 PFASs with relative standard deviations < 15% were achieved. When applied in the analysis of target PFASs in lake water, tap water, beverage, and shrimp muscle samples, this method could achieve robust and accurate results with sufficient sensitivity for nine PFASs.

Determination of anionic perfluorinated compounds in water samples using cationic fluorinated metal organic framework membrane coupled with UHPLC-MS/MS

Global concerns stem from the environmental crisis have compelled researchers to develop selective and sensitive methods for the identification and measurement of emerging pollutants in the environmental matrices. The cationic F-TMU-66⁺Cl^-/polyvinylidene fluoride metal-organic frameworks (MOFs) mixed matrix membrane (F-TMU-66⁺Cl^-/PVDF MMM) was synthesized and used as a versatile adsorbent with multiple binding sites for the simultaneous extraction of twelve anionic perfluorinated compounds (PFCs) from reservoir water samples. The physical and chemical characteristics of the materials, as well as adsorption mechanism were fully surveyed by various instrumental techniques. Important extraction parameters, including amount of MOFs, pH, desorption conditions, and salinity were systematically investigated and optimized. The combination of dispersive membrane solid extraction based on F-TMU-66⁺Cl^-/PVDF MMM with ultra-high performance liquid chromatography-tandem mass spectrometry provided ultra-low limit of detections within the range of 0.03-0.48 ng/L. By virtue of the simplicity and robustness of the extraction procedure, high sensitivity of detection scheme, good stability and selectivity of the F-TMU-66⁺Cl^-/PVDF MMM, the developed method exhibits excellent practicability for ultra-trace analysis of anionic PFCs in water samples.

Biomass magnetic porous carbon prepared from mangosteen shell for the preconcentration of 3 bisphenols from beverages followed by liquid chromatographyquadrupoleorbitrap high-resolution mass spectrometry determination

Natural biomass magnetic porous carbon was successfully prepared via a cost-effective and green route using mangosteen shell as raw material. The prepared magnetic porous carbon was used as a magnetic solid phase extraction adsorbent for bisphenols enrichment from beverages followed by high-performance liquid chromatographyquadrupole Orbitrap high-resolution mass spectrometry. Parameters affecting extraction efficiency including sample solutionpH, adsorbent amount, extraction time, eluent type and volume were optimized. Results showed that biomass magnetic porous carbon had excellent adsorption properties for bisphenols due to its large specific surface area and abundant functional groups, which could form hydrogen bonding and π-π stacking with bisphenols. The enrichment factor of 3 bisphenolswere in the range of15∼19. Under optimum conditions, favorable linearity for all analytes was obtained with correlation coefficients higher than 0.998. Recoveries of spiked samples were in the range of 88.5%∼105.1% with relative standard deviation of 3.4%∼5.5%. These results demonstrated thatmagnetic porous carbon may be a promising adsorbent for enrichment of aromatic compounds. This article is protected by copyright. All rights reserved.

Revealing the Toxicity-Enhancing Essence of Glycyrrhiza on Genkwa Flos Based on Ultra-high-performance Liquid Chromatography Coupled With Quadrupole-Orbitrap High-Resolution Mass Spectrometry and Self-Assembled Supramolecular Technology

Researchers often focus on the mechanisms of synergistic agents, a few explore drug combinations that enhance toxicity, while few have studied the internal mechanism of compatibility enhancement in chemical level. Herein, we present a comprehensive analysis based on ultra-high-performance liquid chromatography coupled with quadrupole-Orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS) and a self-assembled supramolecular strategy, which reveals the toxicity-enhancing essence of glycyrrhizic acid originated in licorice when combined with Genkwa Flos. Through this method, we discovered the toxicity was enhanced through the formation of a supramolecular complex from Genkwa Flos/glycyrrhizic acid. The morphology and size distribution of the self-assembled nanoparticles were characterized by scanning electron microscopy and dynamic light scattering Furthermore, a total of 58 constituents (eight diterpenoids, 35 flavonoids, five phenylpropanoids, four nucleosides, two amino acids, and four other compounds) consisted from the supramolecular complex were identified through accurate-mass measurements in full-scan MS/data-dependent MS/MS mode. Based on the hydrophobic interaction of glycyrrhizic acid with yuanhuacine (one of main ingredients from Genkwa Flos), the supramolecular self-assembly mechanism was revealed with proton nuclear magnetic resonance (¹H-NMR) and NOESY 2D NMR. The toxicity of Genkwa Flos and Genkwa Flos/glycyrrhizic acid supramolecular complex were compared through in vitro studies on L-02 cells using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay; and 4',6-diamidino-2-phenylindole (DAPI) staining was performed to further confirm the enhancement inhibition of Genkwa Flos/glycyrrhizic acid supramolecular complex than Genkwa Flos. This study provides fundamental scientific evidence of the formation of a self-assembled phytochemical supramolecular when Genkwa Flos and glycyrrhizic acid are combined, enabling to understand their clinical incompatibility and contraindication.

Banana-peel-derived magnetic porous carbon as effective adsorbent for the enrichment of six bisphenols from beverage and water samples

Functionalized magnetic nanoporous carbon derived from banana peel was synthesized through carbonization, porogenesis, carboxylation and magnetization using banana peel and was successfully used as a magnetic solid phase extraction (MSPE) material for the enrichment of six bisphenols (BPs) from beverage and water samples. After the optimization of MSPE process, the enrichment factors of six target analytes were in the range of 74-112 for water samples, and 15-22 for beverage samples. Then, high-performance liquid chromatography-quadrupole-Orbitrap high-resolution mass spectrometry (HPLC-Q Orbitrap-HRMS) was used for the separation and determination of the target analytes. Results showed that the extraction recoveries for 6 BPs were in the range of 71.9-108.4% with an RSD of 2.5-7.5% (n = 6). These results demonstrated that the as-prepared material could efficiently enrich some aromatic compounds and the proposed method is reliable and robust for the determination of BPs in water and beverage samples.

Dual-Functionalized MIL-101(Cr) for the Selective Enrichment and Ultrasensitive Analysis of Trace Per- and Poly-fluoroalkyl Substances

The presence of per- and poly-fluoroalkyl substances (PFASs) even at trace levels poses a potential threat to ecological safety and human health. PFASs often require an extraction pretreatment for enrichment before detection and analysis, which is still challenged by the relatively low efficiency because of the limited specific interactions involved. Here, we deliberately introduced multiple interactions into the solid-phase microextraction (SPME) process via a dual-functional modification of MIL-101(Cr), i.e., amination and subsequent fluorination, which is then used as an adsorbent for the efficient enrichment of PFASs. In combination with ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), ultrasensitive quantitative analysis is available for nine selected PFASs with high linearities above 0.9941 in the ranges of 0.5-1500 ng/L, low limits of detection of 0.004-0.12 ng/L, satisfactory repeatability and reproducibility with a relative standard deviation (RSD) < 11.6%, as well as excellent performance in complicated real water samples (recovery ratio of 76.2-108.6%). This work represents a rational design of a solid extractant with the desired structure and functionality for the selective enrichment and analysis of PFASs at trace concentrations in real applications.

Room-temperature synthesis of amino-functionalized magnetic covalent organic frameworks for efficient extraction of perfluoroalkyl acids in environmental water samples

The novel amino-functionalized magnetic covalent organic framework nanocomposites (Fe₃O₄@[NH₂]-COFs) were fabricated at room temperature, which were explored as a magnetic adsorbent for magnetic solid-phase extraction (MSPE). On the basis of the hydrophobic surfaces of magnetic nanocomposites and introduction of primary amines into the COFs shell, Fe₃O₄@[NH₂]-COFs displayed excellent enrichment capacity in "catching" ultratrace perfluoroalkyl acids (PFAAs) from water samples because of the synergistic combination of hydrophobic and electrostatic interactions between PFAAs and Fe₃O₄@[NH₂]-COFs. Under the optimized pretreatment and instrumental parameters, the proposed pretreatment approach, which hybridized MSPE using Fe₃O₄@[NH₂]-COFs and HPLC-MS/MS, displayed favorable linearity (10-10,000 ng L^-1) with R² (0.9990-0.9999), low limits of detection (0.05-0.38 ng L^-1), and excellent repeatability (3.7-9.2%). Moreover, the established approach was successfully utilized to determine PFAAs in real water samples with spiked recoveries ranging from 72.1% to 115.4%. Results indicated that Fe₃O₄@[NH₂]-COFs would be a potential alternative for MSPE of PFAAs at ultra-low levels.

Development and perspectives of rapid detection technology in food and environment

Food safety become a hot issue currently with globalization of food trade and food supply chains. Chemical pollution, microbial contamination and adulteration in food have attracted more attention worldwide. Contamination with antibiotics, estrogens and heavy metals in water environment and soil environment have also turn into an enormous threat to food safety. Traditional small-scale, long-term detection technologies have been unable to meet the current needs. In the monitoring process, rapid, convenient, accurate analysis and detection technologies have become the future development trend. We critically synthesizing the current knowledge of various rapid detection technology, and briefly touched upon the problem which still exist in research process. The review showed that the application of novel materials promotes the development of rapid detection technology, high-throughput and portability would be popular study directions in the future. Of course, the ultimate aim of the research is how to industrialization these technologies and apply to the market.

Determination of bongkrekic acid and isobongkrekic acid in rice noodles by HPLC-Orbitrap HRMS technology using magnetic halloysite nanotubes

The existing extraction and detection methods of bongkrekic acid (BKA) and isobongkrekic acid (IBKA) are complex, time-consuming and solvent-consuming. In this work, a simple and fast pre-concentration procedure based on Fe₃O₄/HNTs was developed for the determination of BKA and IBKA in rice noodles using HPLC-Orbitrap HRMS. The structure and morphology of Fe₃O₄/HNTs was characterized by means of XRD, SEM, FT-IR and VSM. Parameters affecting the extraction efficiency including adsorbent amount, pH, extraction time, type and volume of eluent were investigated by employing the response surface method. Results indicated that the proposed method had favorable linearity in the concentration range of 2-200 μg/L with a correlation coefficient >0.998. Method LOD and LOQ were 0.3 μg/kg and 1.0 μg/kg, respectively. Finally, the method was successfully applied to determine BKA and IBKA in rice noodle samples from southern China with recoveries ranging from 79.8% to 102.6% and relative standard deviation (RSD) of 4.2%-7.1%.

Effective enrichment and detection of trace polybrominated diphenyl ethers in water samples based on magnetic covalent organic framework nanospheres coupled with chromatography-mass spectrometry

Novel core shell structured magnetic covalent organic frameworks were synthesized at room temperature and first applied in water samples for the enrichment of trace polybrominated diphenyl ethers (PBDEs) through magnetic solid-phase extraction. The prepared materials were characterized through transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, vibrating sample magnetometer and X-ray photoelectron spectroscopy. During adsorption, the parameters affecting extraction and desorption efficiency were further optimized. Combined gas chromatography and mass spectrometry (GC/MS) revealed that high enrichment factors (275-292), low limits of detection (0.12-0.38 ng·L-1), wide linear ranges (0.5-1000 ng·L-1), and good reproducibility (intra-day 1.40%-4.31% and inter-day 5.14%-9.12%) were obtained under optimal conditions. The method successfully detected PBDEs in different water samples.

The Current Role of Graphene-Based Nanomaterials in the Sample Preparation Arena

Since its discovery in 2004 by Novoselov et al., graphene has attracted increasing attention in the scientific community due to its excellent physical and chemical properties, such as thermal/mechanical resistance, electronic stability, high Young's modulus, and fast mobility of charged atoms. In addition, other remarkable characteristics support its use in analytical chemistry, especially as sorbent. For these reasons, graphene-based materials (GBMs) have been used as a promising material in sample preparation. Graphene and graphene oxide, owing to their excellent physical and chemical properties as a large surface area, good mechanical strength, thermal stability, and delocalized π-electrons, are ideal sorbents, especially for molecules containing aromatic rings. They have been used in several sample preparation techniques such as solid-phase extraction (SPE), stir bar sorptive extraction (SBSE), magnetic solid-phase extraction (MSPE), as well as in miniaturized modes as solid-phase microextraction (SPME) in their different configurations. However, the reduced size and weight of graphene sheets can limit their use since they commonly aggregate to each other, causing clogging in high-pressure extractive devices. One way to overcome it and other drawbacks consists of covalently attaching the graphene sheets to support materials (e.g., silica, polymers, and magnetically modified supports). Also, graphene-based materials can be further chemically modified to favor some interactions with specific analytes, resulting in more efficient hybrid sorbents with higher selectivity for specific chemical classes. As a result of this wide variety of graphene-based sorbents, several studies have shown the current potential of applying GBMs in different fields such as food, biological, pharmaceutical, and environmental applications. Within such a context, this review will focus on the last five years of achievements in graphene-based materials for sample preparation techniques highlighting their synthesis, chemical structure, and potential application for the extraction of target analytes in different complex matrices.