A hybrid material composed of graphitic carbon nitride and magnetite (Fe3O4) for magnetic solid-phase extraction of trace levels of hydroxylated polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons in water environments: Impact, legislation, depollution processes and challenges, and magnetic iron oxide/graphene-based nanocomposites as promising adsorbent solutions

Environmental pollution is a big challenge of today's world, as population continues to grow, and industrialisation and urbanisation increase. Out of the different micropollutants in the atmosphere and aquatic environments, polycyclic aromatic hydrocarbons are of particular importance because they have known severe associated health risks to human life and they have high stability, leading to their persistence in the environment. They are generally present in the environment in low concentrations, but, even at these levels, they pose threats. This review thus focuses on this family of pollutants, on their occurrence and consequences, as well as the current methodologies employed to remove them from water environments and the challenges that remain. This work then focuses on the potential of magnetic iron oxide/graphene nanocomposites for the adsorption of PAHs, extensively discussing past and undergoing works, as well as the interactions between these adsorbents and PAHs.

Application of nanomaterials for determination and removal of polycyclic aromatic hydrocarbons in food products: A review

Polycyclic aromatic hydrocarbons (PAHs), toxic persistent pollutants, result in adverse impacts to human being health. Among the variety contaminant remediation approaches, nanotechnology was found promising in terms of its efficiency and exceptional size-dependent properties. Nanomaterials also possess high particular surface area, rapid dissolution characteristics, high sorption, magnetic -properties and quantum confinement. Nanoparticles (NPs) have been employed as sorbents in the assessment of PAHs, including carbon NPs, mesoporous silica NPs, metallic species, metal oxides, as well as magnetic and magnetized NPs. Magnetic nanocomposites have demonstrated high efficiency (>99 %) in removing PAHs from food products. Similarly, a magnetic chitosan/molybdenum disulfide nanocomposite exhibited excellent adsorption capacities for PAHs in milk samples. Present research was conducted on multiple academic platforms, including Google Scholar, Science Direct, Elsevier, Springer, Scopus, and PubMed from 2017 to 2024. Various combinations of keywords, such as "PAHs," "extraction," "removal," and "nanomaterials," were used in the search. The aim of this manuscript is to reviews the application of nanotechnologies for the elimination and extraction of PAHs from contaminated food products. The findings of this study offer novel insights into efficient and cost-saving approach and suggest the potential of NPs as promising agents for preconcentration and remediation of PAHs from variety food samples. Also, the obtained results will pave the way for future explorations that will lead to the achievement of maximum efficiency for the analysis and extraction of materials in more diverse matrices. Therefore, it is suggested to investigate the potential of various nanomaterials regarding various matrices in future.

Self-assembled Fe3O4-NH2 @g-C3N4 composite for magnetic solid-phase extraction of benzophenones in sea water and lake water coupled with LC-MS/MS determination

Magnetic solid-phase extraction (MSPE) was developed based on a well-designed Fe3O4-NH2 @g-C3N4 nanocomposite as sorbent for a mixture of six benzophenones (BPs) in environmental water samples. The composite fabricated via in-situ self-assembled g-C3N4 shell with homogeneous polymerization of cyanuric chloride and cyanuric acid on Fe3O4-NH2 core. While high adsorption capacity was derived from g-C3N4 via hydrophobic, π-π and hydrogen bonding interactions to the targets, the fast magnetic separation was realized with Fe3O4 core for less solvent consumption. In combination with LC-MS/MS, the Fe3O4-NH2 @g-C3N4 sorbent minimized the interfering components, reduced the matrix effects, and provided the enrichment factors of 121-150 for six BPs with relative standard deviations ≤ 9.7% even after 20 times extraction-desorption cycles. The present method gave the detection limits of 0.3-2.5 ng/L for six BPs with the linear ranges of 1.0-2000 ng/L, and the recoveries of 84.6%-104% in sea water and 86.2%-107% in lake water samples. Thus, the Fe3O4-NH2 @g-C3N4-based MSPE coupled with LC-MS/MS method provided a convenient, efficient, and reliable alternative to monitor trace BPs in environmental water samples.

Physisorption Behaviors of Organochlorine Pesticides on the InP3 Monolayer from Theoretical Insight

Dichlorodiphenyltrichloroethane (DDT), hexachlorocyclohexane (BHC), aldrin, and chlordimeform are ubiquitous organochlorine pesticide (OCP) residues in the environment, which pose a great threat to human health and ecosystems due to their high toxicity and easy accumulation. Based on the density functional theory (DFT) calculations, a two-dimensional InP3 monolayer was selected as a sensing material to study the sensitivity detection and adsorption behaviors toward BHC, aldrin, chlordimeform, and DDT. The calculation results show that four pesticide molecules are adsorbed on the InP3 surface by physical interaction. The identified response values (69.1, -43.1%) for DDT and chlordimeform reveal the potential of the InP3 monolayer as a sensing material for the detection of these two pesticides, accompanied by the achievement of cyclic utilization by heating to 498 K. The most satisfactory result is the adsorption of BHC, owing to the admirable sensing response (62.7%) and short recovery time (1.8 s) at room temperature, which makes InP3 a promising pesticide sensor for BHC. However, the InP3 surface is unsuitable for aldrin sensing due to poor response (-1.9%). Our work gives theoretical insight into the good sensitivity and recycling of the InP3 monolayer as a new pesticide sensor to detect DDT, BHC, and chlordimeform, which further broadens the application prospect of the InP3 nanosheet into the sensitive detection of organochlorine pesticides in the ecological environment.

A hierarchical porous composite magnetic sorbent of reduced graphene oxide embedded in polyvinyl alcohol cryogel for solvent assisted-solid phase extraction of polycyclic aromatic hydrocarbons

A hierarchical porous composite magnetic sorbent was fabricated and applied to the dispersive solvent assisted-solid phase extraction of five polycyclic aromatic hydrocarbons. A sorbent was first prepared by incorporating graphene oxide, calcium carbonate and magnetite nanoparticles into a polyvinyl alcohol cryogel. The graphene oxide was converted to reduced graphene oxide using ascorbic acid and a hierarchical porous structure was produced by reacting hydrochloric acid with incorporated calcium carbonate to generate carbon dioxide bubbles which created a second network. Before extracting the target analytes, extraction solvent was introduced into the hierarchical pore network of the sorbent. The extraction was based on the partition between the analytes and introduced extraction solvent and the adsorption of analytes on reduced graphene oxide. The extraction efficiency was enhanced through π-π and hydrophobic interactions between polycyclic aromatic hydrocarbons and reduced graphene oxide and extraction solvent. The extracted polycyclic aromatic hydrocarbons were determined using HPLC coupled with fluorescence detector. The developed method was applied to extract polycyclic aromatic hydrocarbons in disposable diaper, coffee and tea samples and recoveries from 84.5 to 99.4% were achieved with relative standard deviations below 7%. The developed sorbent exhibited good reproducibility and can be reused for ten cycles. This article is protected by copyright. All rights reserved.

Recent Advances in Solid-Phase Extraction as a Platform for Sample Preparation in Biomarker Assay

Low levels of biomarkers and the complexity of bio sample make the analytical assay of several biomarkers a challenging issue. Suitable sample preparation run remain a vital part of the puzzle of diagnostic level. Enhancing the detection limit of bioanalytical methods start during the sample preparation procedure. A robust sample preparation method is needed to evaluate the number of biomarkers. As worldwide environmental issues attract expanding consideration, all the more harmless to the ecosystem investigations are liked. Solid-phase extraction (SPE) is an appealing strategy among the sample treatment methods due to the versatility of sorbent materials, less solvent consumption, and compatibility with analytical devices. Miniaturization of the SPE gives the chance to integrate the other analytical steps in a single run, known as an easy-to-use and effective method. SPE utilizes various SPE sorbent beds such as packed beads, porous polymer monoliths, molecularly imprinted polymers, membranes, or other magnetic form microstructures to achieve high surface-to-volume ratio and appropriate chemical properties effective extraction. Also, SPE is the methodology of interest to fulfill high recovery and efficiency demands. In this review, we intend to explain more recent methods for the rational design of SPE and miniaturized SPE to determine biomarkers from biological media. The headlines are subdivided into (1) packing materials in SPE, (2) setups for sample preparation by magnetic SPE, and (3) and future perspective for the application of SPE in sample preparation for analysis of biomarkers.

Fabrication of magnetic polydopamine@naphthyl microporous organic network nanosphere for efficient extraction of hydroxylated polycyclic aromatic hydrocarbons and p-nitrophenol from wastewater samples

Herein, we report the fabrication of a novel, well-defined core-double-shell-structured magnetic Fe₃O₄@polydopamine@naphthyl microporous organic network (MON), Fe₃O₄@PDA@NMON, for the efficient magnetic extraction of hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) and p-nitrophenol (p-Npn) from wastewater samples. The hierarchical nanospheres were designed and constructed with the Fe₃O₄ nanoparticle core, the inner shell of a polydopamine (PDA) layer, and the outer shell of a porous naphthyl MON (NMON) coating, allowing efficient and synergistic extraction of OH-PAHs and p-Npn via hydrophobic, hydrogen bonding, and π-π interactions. The Fe₃O₄@PDA@NMON nanospheres were well characterized and employed as an efficient sorbent for magnetic solid-phase extraction (MSPE) coupled with high performance liquid chromatography (HPLC) for analyzing of OH-PAHs and p-Npn. Under optimal conditions, the Fe₃O₄@PDA@NMON-based-MSPE-HPLC-UV method afforded wide linear range (0.18-500 μg L^-1), low limits of detection (0.070 μg L^-1 for p-Npn, 0.090 μg L^-1 for 2-OH-Nap, 0.090 μg L^-1 for 9-OH-Fluo and 0.055 μg L^-1 for 9-OH-Phe, respectively), large enrichment factors (92.6-98.4), good precisions (intra-day and inter-day relative standard deviations (RSDs); <6.4%, n=6) and less consumption of the adsorbent. Furthermore, trace OH-PAHs and p-Npn with concentrations of 0.29-0.80 μg L^-1 were successfully detected in various wastewater samples. Fe₃O₄@PDA@NMON also functioned as a good adsorbent to enrich a wide scope of trace contaminants containing hydrogen bonding sites and aromatic structures, highlighting the potential of functional MONs in sample pretreatment.

Porous cage-like hollow magnetic carbon-doped CoO nanocomposite as an advanced sorbent for magnetic solid-phase extraction of nine polycyclic aromatic hydrocarbons

In this study, porous cage-like hollow magnetic carbon-doped CoO nanocomposite (CoO@C) was successfully synthesized using a metal-organic frameworks (MOFs) as precursor by one-step calcination method in this work. The obtained nanoporous composite showed excellent magnetic response by taking advantage of the magnetism of CoO even without the Fe₃O₄, making it an advanced sorbent for magnetic solid-phase extraction (MSPE). The Co-MOF and CoO@C were characterized by XRD, TGA, SEM, TEM, vibrating sample magnetometry, and FT-IR spectroscopy. Based on this, a method using CoO@C for MSPE coupled with HPLC was established for the analysis of nine polycyclic aromatic hydrocarbons (PAHs) from various real water samples. The amount of sorbent, extraction times, extraction temperature, desorption times, oscillation rate, and elution volume were optimized. Under the optimal conditions, the method had good relative standard deviations (RSDs) of 1.1%-6.5% and a satisfying linearity range of 0.5-1000 μg L^-1. The low LOD and LOQ for nine PAHs were found to be 0.06-1.30 μg L^-1 and 0.19-4.30 μg L^-1, respectively. The experimental results indicated that the prepared nanocomposite showed excellent adsorption capacity compared to other commercial sorbents and has potential applications for the removal of hazardous pollutants from environmental samples.

Advances in water treatment technologies for removal of polycyclic aromatic hydrocarbons: Existing concepts, emerging trends, and future prospects

In the last two decades, environmental experts have focused on the development of several biological, chemical, physical, and thermal methods/technologies for remediation of PAH-polluted water. Some of the findings have been applied to field-scale treatment, while others have remained as prototypes and semi-pilot studies. Existing treatment options include extraction, chemical oxidation, bioremediation, photocatalytic degradation, and adsorption (employing adsorbents such as biomass derivatives, geosorbents, zeolites, mesoporous silica, polymers, nanocomposites, and graphene-based materials). Electrokinetic remediation, advanced phytoremediation, green nanoremediation, enhanced remediation using biocatalysts, and integrated approaches are still at the developmental stage and hold great potential. Water is an essential component of the ecosystem and highly susceptible to PAH contamination due to crude oil exploration and spillage, and improper municipal and industrial waste management, yet comprehensive reviews on PAH remediation are only available for contaminated soils, despite the several treatment methods developed for the remediation of PAH-polluted water. This review seeks to provide a comprehensive overview of existing and emerging methods/technologies, in order to bridge information gaps toward ensuring a green and sustainable remedial approach for PAH-contaminated aqueous systems. PRACTITIONER POINTS: Comprehensive review of existing and emerging technologies for remediation of PAH-polluted water. Factors influencing efficiency of various methods, challenges and merits were discussed. Green nano-adsorbents, nano-oxidants and bio/phytoremediation are desirous for ecofriendly and economical PAH remediation. Adoption of an integrated approach for the efficient and sustainable remediation of PAH-contaminated water is recommended.

The Role of Suspension Array Technology in Rapid Detection of Foodborne Pollutants: Applications and Future Challenges

Food safety is an important livelihood issue, which has always been focused attention by countries and governments all over the world. As food supply chains are becoming global, food quality control is essential for consumer protection as well as for the food industry. In recent years, a great part of food analysis is carried out using new techniques for rapid detection. As the first biochip technology that has been approved by the Food and Drug Administration (FDA), there is an increasing interest in suspension array technology (SAT) for food and environmental analysis with advantages of rapidity, high accuracy, sensitivity, and throughput. Therefore, it is important for researchers to understand the development and application of this technology in food industry. Herein, we summarized the principle and composition of SAT and its application in food safety monitoring. The utility of SAT in detection of foodborne microorganisms, residues of agricultural and veterinary drugs, genetically modified food and allergens in recent years is elaborated, and the further development direction of SAT is envisaged.

Fully automated graphitic carbon nitride-based disposable pipette extraction-gas chromatography-mass spectrometric analysis of six polychlorinated biphenyls in environmental waters

A fully automated online emulsification-enhanced disposable pipette extraction-gas chromatography-mass spectrometry (EE-DPX-GC-MS) method has been developed for the extraction of six polychlorinated biphenyls (PCBs) from environmental waters. An in-house prepared material, graphitic carbon nitride (g-C₃N₄), was used as sorbent in a home-packed DPX device. The six PCBs studied include PCB 10, 28, 52, 153, 138 and 180. g-C₃N₄ was characterized successfully by X-ray diffraction, elemental analysis, scanning electron microscopy, Fourier-transform infrared and Raman spectroscopy. As a C-N analogue of graphite, the two-dimensional structure of g-C₃N₄ allows rapid analyte adsorption and desorption to take place. With a significant number of nitrogen functionalities in g-C₃N₄, the material dispersed well in aqueous sample, increasing the active surface area of contact between the sorbent and the sample. When coupled with a pre-emulsification step, PCBs in each portion of sample could be efficiently extracted by g-C₃N₄ within 20 s of gentle turbulence. Under the most favorable conditions, the automated online EE-DPX-GC-MS method achieved wide dynamic working ranges with good linearity (r² ≥ 0.998) for all analytes. Limits of detection ranging between 4.35 and 7.82 ng L^-1 were attained, with enrichment factors of between 34 and 57 and relative standard deviations (RSDs) for intra- and inter-day precision of ≤ 8.95% and ≤ 12.6%, respectively. Absolute recoveries were between 69.3% and 109%. The fully automated online EE-DPX-GC-MS approach was applied to industrial wastewaters and reservoir waters where good relative recoveries of PCBs of between 89.3% and 105% were obtained, with RSDs ≤ 11.6%.

Insights into the structure-performance relationships of extraction materials in sample preparation for chromatography

Sample preparation is one of the most crucial steps in analytical processes. Commonly used methods, including solid-phase extraction, dispersive solid-phase extraction, dispersive magnetic solid-phase extraction, and solid-phase microextraction, greatly depend on the extraction materials. In recent decades, a vast number of materials have been studied and used in sample preparation for chromatography. Due to the unique structural properties, extraction materials significantly improve the performance of extraction devices. Endowing extraction materials with suitable structural properties can shorten the pretreatment process and improve the extraction efficiency and selectivity. To understand the structure-performance relationships of extraction materials, this review systematically summarizes the structural properties, including the pore size, pore shape, pore volume, accessibility of active sites, specific surface area, functional groups and physicochemical properties. The mechanisms by which the structural properties influence the extraction performance are also elucidated in detail. Finally, three principles for the design and synthesis of extraction materials are summarized. This review can provide systematic guidelines for synthesizing extraction materials and preparing extraction devices.

Fast and simple determination of estrogens in milk powders by magnetic solid-phase extraction using carbon nitride composites prior to HPLC

A graphitic carbon nitride (g-C₃N₄/Fe₃O₄)-based magnetic solid-phase extraction (MSPE) approach was established for fast and simple analysis of estrogens in milk powders. The composites were characterized by X-ray diffractometer, scanning electron microscope, and Brunauer-Emmett-Teller surface area and pore size distribution analyzer. Compared with the bulk g-C₃N₄, g-C₃N₄/Fe₃O₄ gave a narrower distribution of mesopores and provided an enhanced surface area from 77.1 to 113.7 m²/g. Polar analytes of estrogens were selected as model compounds and the extraction of four estrogens was achieved in n-hexane using 15 mg of adsorbent within only 2 min. Possible extraction mechanism of g-C₃N₄/Fe₃O₄ for these estrogens was explored in terms of the polarity of the analytes and the adsorption performance of the adsorbent. The hydrophobicity and the hydrogen-bond interaction between the estrogens and g-C₃N₄ were responsible for the efficient adsorption. Combined with HPLC, MSPE with the prepared adsorbent gave the enhancement factors of 20 to 24 and the linear ranges of 2-200 μg/kg for 17β-estradiol and 17α-ethinylestradiol, 1.5-150 μg/kg for estrone, and 3-300 μg/kg for hexestrol. The detection limits and quantification limits for the estrogens in milk powders were 0.5-0.9 μg/kg and 1.5-3.0 μg/kg, respectively. The recoveries varied from 75.1 to 97.2%, with the intra-day and inter-day precisions ≤ 14.2%. Furthermore, the enrichment of the analytes and the clean-up of fat and protein interferences were achieved simultaneously with one-step g-C₃N₄-based MSPE. The present method was convenient, fast, and sensitive, and therefore could be successfully applied for the determination of estrogens in milk powders. Graphical abstract.

A "half" core-shell magnetic nanohybrid composed of zeolitic imidazolate framework and graphitic carbon nitride for magnetic solid-phase extraction of sulfonylurea herbicides from water samples followed by LC-MS/MS detection

A "half" core-shell g-C₃N₄/Fe₃O₄@ZIF-8 nanohybrid, in which Fe₃O₄ and zeolite imidazolate framework-8 (ZIF-8) constructed the core-shell structure, was successfully fabricated via a versatile in situ growth strategy. This nanohybrid was employed for simultaneous magnetic solid-phase extraction (MSPE) of trace levels of fifteen target sulfonylurea herbicides (SUHs) in environmental water samples followed by LC-MS/MS detection. C₃N₄ nanosheets were first prepared by liquid exfoliation of bulk g-C₃N₄, after which Fe₃O₄ nanoparticles were uniformly deposited onto the surface of C₃N₄ nanosheets, and ZIF-8 nanoparticles were grown on the surface of g-C₃N₄/Fe₃O₄ by anchoring Zn²⁺ on g-C₃N₄/Fe₃O₄. Owing to the synergistic effect, the hybridization of C₃N₄ and ZIF-8 endowed the nanohybrid with higher multi-target adsorption ability for SUHs compared to pure C₃N₄ or ZIF-8. The separation as well as the enrichment processes were facilitated using Fe₃O₄ as a magnetic core. The influence of various parameters on MSPE efficiency, including adsorbent dosage, extraction time, solution pH, and desorption solvent and its volume, was investigated in detail. Under optimal conditions, the MSPE coupled with LC-MS/MS exhibited good linearity ranging from 0.5 to 100 μg L^-1 with correlation coefficients (R²) ≥ 0.9919, high sensitivity with low limits of detection (LODs) of 0.005-0.141 μg L^-1 and satisfactory recoveries of 67.4-105.5% with relative standard deviations (RSDs) < 9.8%. These results indicate that this method is reliable for the determination of SUHs in different matrices and the in situ growth strategy is a promising approach for constructing effective adsorbents. Graphical abstract Schematic representation of a "half" core-shell magnetic nanohybrid composed of zeolitic imidazolate framework (ZIF-8) and graphitic carbon nitride (g-C₃N₄) for magnetic solid-phase extraction (MSPE) of trace level determination of fifteen sulfonylurea herbicides (SUHs) in environmental water samples using LC-MS/MS detection.