Novel functionalized magnetic ionic liquid green separation technology coupled with high performance liquid chromatography: A rapid approach for determination of estrogens in milk and cosmetics

Magnetic conjugated microporous polymer for rapid extraction and sensitive analysis of environmental endocrine disruptors in environmental waters and dairy products

BACKGROUND

Environmental endocrine disruptors (EEDs) are a class of new pollutants that are diffusely used in the medical industry and animal husbandry. In view of toxicity concerns, elevated levels of EEDs in the environment and food, which cause potential harm to human beings and ecosystems, must be monitored. Determination of EEDs contaminants to ensure environment and food safety has became a major concern worldwide, it is also a challenging task because of their trace level and probable matrices interference. Thus, developing rapid adsorption and efficient analysis methods for EEDs is apparently necessary.

RESULTS

A magnetic conjugated micro-porous polymer (Fe3O4@TbDt) was designed and synthesized, which was endowed with large specific surface area, rich functional groups and magnetic responsiveness. The material showed high extraction efficiency for EEDs via magnetic solid-phase extraction (MSPE). The quantum chemistry calculations showed the adsorption mechanism of Fe3O4@TbDt on EEDs mainly included electrostatic interactions, van der waals forces (N-H … π interaction, C-H … π interaction), and multiple hydrogen bonds. Finally, a trace analysis method for nine EEDs was established combined with HPLC-MS/MS under optimized MSPE conditions. The method showed a good linearity (R2 ≥ 0.996), low limits of detection (0.25-5.1 ng L-1), high precision (RSD of 1.1-8.2 %, n = 6). The applicability of this method was investigated by analyzing four water samples and two dairy products, and satisfactory recovery rates (82.1-100.7 %) were obtained. The proposed method showed the potential for the analysis of EEDs residues in food and environmental samples.

SIGNIFICANCE

The developed MSPE method based on conjugated micro-porous polymers (CMPs) is simple, green, and efficient compared to existing techniques. The application of CMPs provides a new idea for preparing versatile sample pre-treatment materials. What's more, this work has certain reference value for addressing of EEDs residues in the environment and food.

Preparation of a sustainable magnetic sorbent for the extraction and preconcentration of progestogens in natural water samples

A film composed of agarose and graphene (G) and magnetic nanoparticles (G-MNPs) is proposed as a sorbent for the extraction and determination of medroxyprogesterone (MED), levonorgestrel (LEV), norethisterone (NOR) and progesterone (PRO) in natural water samples. Both the preparation of the film and the extraction procedure were optimized. The optimal extraction parameters were as follows: isopropyl alcohol as activation solvent, sample pH value of 3.0, extraction time of 30 min, 1.00 mL of acetonitrile as eluent, elution time of 5 min and sample volume of 100.00 mL. HPLC with photodiode array detector was used for the separation and determination. The method presented a linear range between 2.50 and 75.0 μg L-1 for all analytes, and the LODs were between 1.40 and 1.80 μg L-1. The method was applied to natural water samples, obtaining satisfactory recovery values (75-111 %). In conclusion, for the immobilization of the G-MNPs, agarose was used, which is a non-toxic, renewable and biodegradable material. The G-MNPs-agarose film was reused up to 70 times, without losing its extraction capacity significantly and presenting excellent sorbent properties, which allow the extraction and preconcentration of the progestogens under study.

Fabrication of imidazoline-linked cationic covalent triazine framework for enrichment of environmental estrogens

Imidazoline-linked cationic covalent triazine framework (IM-iCTF) was facilely prepared through the Debus-Radziszewski reaction, involving 4,4',4''-(1,3,5-triazine-2,4,6-triyl)trianiline, formaldehyde and methylglyoxal. The IM-iCTF was applied as a sorbent for cartridge solid-phase extraction (SPE). It provided good adsorption performance for estrogen and estrogen mimics including bisphenol F, bisphenol A, 7β-estradiol, bisphenol B and estrone. The adsorption isotherm, adsorption kinetic model, thermodynamic calculations and adsorption mechanism were investigated to reveal the adsorption behavior. The IM-iCTF was employed for the extraction of the estrogens and estrogen mimics from water, fish and shrimp (fish and shrimp samples were extracted with acetonitrile before the SPE). The analytes were then determined by high-performance liquid chromatography with diode array detection. The limits of detection were 0.008-0.05 ng mL-1 for water, 0.015-0.11 μg g-1 for fish, and 0.012-0.10 μg g-1 for shrimp samples. This research not only offers a new approach to construct cationic covalent triazine framework, but also provides a reliable strategy for the adsorption/enrichment trace level of organic pollutants.

Membrane-protected magnetic covalent organic framework for efficient extraction of estrogens in dairy products

The presence of estrogens residues in dairy products is a growing concern due to their potential health risk. Herein, in this study, we have developed a membrane-protected magnetic solid-phase extraction (MP-MSPE) method that utilized a magnetic adsorbent (Fe3O4@COF-LZU1) with in-situ growth for the efficient extraction of estrone (E1), 17β-estradiol (E2), and estriol (E3). When combined with HPLC-FLD, this method allows for the efficient detection of estrogens in dairy products. The stability of the MP-MSPE was improved by the presence of a dialysis membrane, which remained a high extraction efficiency (90 %) even after ten reuse cycles. The hydrogen bonding, π-π interactions and pore size effect contribute to the excellent adsorption of three estrogens onto Fe3O4@COF-LZU1. Under optimal conditions, the method exhibits a low detection limit (0.01-0.15 μg L-1), wide linear range (0.1-800 μg L-1), and favorable recoveries (77.3 %-109.4 %) at three concentration levels (10, 50 and 100 μg L-1). This proposed method is characterized by its simplicity, high efficiency and eco-friendliness, making it a promising approach for extracting estrogens from dairy products.

Magnetic Ionic Liquids: Current Achievements and Future Perspectives with a Focus on Computational Approaches

Magnetic ionic liquids (MILs) stand out as a remarkable subclass of ionic liquids (ILs), combining the desirable features of traditional ILs with the unique ability to respond to external magnetic fields. The incorporation of paramagnetic species into their structures endows them with additional attractive features, including thermochromic behavior and luminescence. These exceptional properties position MILs as highly promising materials for diverse applications, such as gas capture, DNA extractions, and sensing technologies. The present Review synthesizes key experimental findings, offering insights into the structural, thermal, magnetic, and optical properties across various MIL families. Special emphasis is placed on unraveling the influence of different paramagnetic species on MILs' behavior and functionality. Additionally, the Review highlights recent advancements in computational approaches applied to MIL research. By leveraging molecular dynamics (MD) simulations and density functional theory (DFT) calculations, these computational techniques have provided invaluable insights into the underlying mechanisms governing MILs' behavior, facilitating accurate property predictions. In conclusion, this Review provides a comprehensive overview of the current state of research on MILs, showcasing their special properties and potential applications while highlighting the indispensable role of computational methods in unraveling the complexities of these intriguing materials. The Review concludes with a forward-looking perspective on the future directions of research in the field of magnetic ionic liquids.

What Are We Eating? Surveying the Presence of Toxic Molecules in the Food Supply Chain Using Chromatographic Approaches

Consumers in developed and Western European countries are becoming more aware of the impact of food on their health, and they demand clear, transparent, and reliable information from the food industry about the products they consume. They recognise that food safety risks are often due to the unexpected presence of contaminants throughout the food supply chain. Among these, mycotoxins produced by food-infecting fungi, endogenous toxins from certain plants and organisms, pesticides, and other drugs used excessively during farming and food production, which lead to their contamination and accumulation in foodstuffs, are the main causes of concern. In this context, the goals of this review are to provide a comprehensive overview of the presence of toxic molecules reported in foodstuffs since 2020 through the Rapid Alert System for Food and Feed (RASFF) portal and use chromatography to address this challenge. Overall, natural toxins, environmental pollutants, and food-processing contaminants are the most frequently reported toxic molecules, and liquid chromatography and gas chromatography are the most reliable approaches for their control. However, faster, simpler, and more powerful analytical procedures are necessary to cope with the growing pressures on the food chain supply.

Nanoconfinement of functionalized ionic liquid for enhanced adsorption and rapid sensitive detection of phenylurea herbicides in food and environmental samples

The novel ILs@CNTs was synthesized by encapsulating task-specific ionic liquids (ILs) within carbon nanotubes (CNTs) derived from ZIF-67. These hybrid materials served as multifunctional adsorbents enabling simultaneous sorptive removal, sensitive detection, molecular sieve selection, and magnetic separation. In contrast to pristine CNTs, ILs@CNTs demonstrate significantly enhanced adsorption of phenylurea herbicides (PUHs). The complex interactions between ILs@CNTs and PUHs were comprehensively analyzed using a combination of experimental results and theoretical calculations. Furthermore, a magnetic solid phase extraction-high performance liquid chromatography (MSPE-HPLC) method was developed for the determination of multiple trace PUHs in real samples. The method exhibited lower detection limits (0.02-0.03 μg L-1) and higher enrichment factors (131 < EFs < 185). Interestingly, a portable lab-in-a-syringe device was developed to facilitate rapid on-site extraction and enrichment of PUHs. Additionally, the developed methods successfully applied in river water, tea drinks, and cucumber samples, highlighting its substantial potential for rapid PUH detection.

Optimization of [P6,6,6,14+]3[GdCl63-] magnetic ionic liquid assisted dispersive liquid-liquid microextraction for selective and sensitive determination of cadmium in environmental water and food

A simple and green hydrophobic magnetic ionic-liquid assisted dispersive liquid-liquid microextraction (MIL-DLLME) was optimized for the determination of trace cadmium (Cd (II)) in environmental and food samples by flame atomic absorption spectrophotometer. To achieve selective and sensitive extraction of Cd (II), four MILs were prepared and tested. Extraction parameters of the MIL-DLLME including pH, type and volume of the MIL, type and volume of dispersive solvent, extraction cycle, ionic strength and sample volume were investigated in detail and optimized by Box-Behnken design. Under optimum conditions, matrix effect, recovery study, intra-day and inter-day precision were performed for the MIL-DLLM. The analytical characteristics such as limit of detection, limit of quantification and pre-concentration factor were 0.17, 0.56 and 125 ng mL-1, respectively. The validation of the MIL-DLLME was evaluated by analysis of reference materials. Moreover, the accuracy of the results in the analysis of real samples was evaluated by standard addition and quantitative recoveries (91 ± 5-101 ± 2%) were achieved. The results obtained in the analysis of both reference materials and real samples showed that the MIL-DLLME has a selective applicability for cadmium.

Inline phase transition trapping-selective supercritical fluid extraction-supercritical fluid chromatography: A green and efficient integrated method for determining prohibited substances in cosmetics

BACKGROUND

Developing an environmentally friendly and efficient integrated analytical approach is a cutting-edge topic in current analytical science. Due to the unique properties of supercritical carbon dioxide (sc-CO2), online supercritical fluid extraction-supercritical fluid chromatography (SFE-SFC) is developing rapidly and has been widely applied in many fields. However, it still faces several challenges such as peak broadening and matrix interference. In order to solve the problems, we developed an inline phase transition trapping-selective supercritical fluid extraction-supercritical fluid chromatography (PTT-SSFE-SFC)-tandem mass spectrometry (MS/MS) method in this study.

RESULTS

This method integrated extraction, purification, separation, and detection, which was applied to determine 114 prohibited substances in cosmetics within 33 min, covering ten categories. The PTT strategy trapped the extracts on the head of the column by transforming CO2 from a supercritical state to a gaseous state, preventing peak spreading and improving sensitivity. Several adsorbents were tested when analyzing aqueous samples to reduce matrix interference and absorb water. Compared with conventional online SFE-SFC, this method improved the matrix effects of 93 and 87 target substances in the toner and mask matrix, respectively. Because the integrated method reduced sample loss, it achieved high sensitivity with LODs ranging from 0.00104 μg L-1 to 3.09 μg L-1. Furthermore, compared with other reported green methods, the inline method showed advantages in automation, efficiency, sample amount, and waste volume.

SIGNIFICANCE AND NOVELTY

With the introduction of the PTT strategy and the adsorbent, the system obtained good peak shapes, high sensitivity, low matrix effect, and good recovery. Based on the results, inline PTT-SSFE-SFC-MS/MS as a green and efficient integrated method has great potential for analyzing low abundance and multiple categories of targets in complex samples.

Applications of mass spectrometry in cosmetic analysis: An overview

Mass spectrometry (MS) is a crucial tool in cosmetic analysis. It is widely used for ingredient screening, quality control, risk monitoring, authenticity verification, and efficacy evaluation. However, due to the diversity of cosmetic products and the rapid development of MS-based analytical methods, the relevant literature needs a more systematic collation of information on this subject to unravel the true potential of MS in cosmetic analysis. Herein, an overview of the role of MS in cosmetic analysis over the past two decades is presented. The currently used sample preparation methods, ionization techniques, and types of mass analyzers are demonstrated in detail. In addition, a brief perspective on the future development of MS for cosmetic analysis is provided.

Diluting modulation-based two dimensional-liquid chromatography coupled with mass spectrometry for simultaneously determining multiclass prohibited substances in cosmetics

Developing efficient and comprehensive screening methods for prohibited substances in cosmetics is critical for ensuring the quality and safety of cosmetics used in everyday life. This study proposed a heart-cutting two-dimensional liquid chromatography-mass spectrometry (2D-LC-MS) method based on online diluting modulation for detecting multiclass prohibited substances in cosmetics. The 2D-LC-MS method combines HILIC and RPLC techniques. Compounds near the dead time that the first dimensional HILIC could not separate were transferred to the second dimensional RPLC by valve switch, achieving good separation with a wide range of polarities. Moreover, the online diluting modulation solved the problem of mobile phase incompatibility, realizing an excellent column-head focusing effect and reducing the loss of sensitivity. Besides, the first dimensional analysis did not restrict the flow rate of the second dimensional analysis owing to the diluting modulation. We demonstrated the 2D-LC-MS system by determining 126 prohibited substances in cosmetic products, including hormones, local anesthetics, anti-infectives, adrenergic agents, antihistamines, pesticides, and other chemicals. All correlation coefficients of the compounds were above 0.9950. The LODs and the LOQs ranged from 0.000259 ng/mL to 16.6 ng/mL and 0.000864 ng/mL to 55.3 ng/mL, respectively. The RSDs% for intra-day and inter-day precision were within 6% and 14%, respectively. Compared with conventional one-dimensional liquid chromatography methods, the established method expanded the analytical coverage of cosmetics-prohibited substances with reduced matrix effects for most compounds and improved sensitivity for polar analytes. The results indicated that the 2D-LC-MS method was a powerful tool for screening multiclass prohibited substances in cosmetics.

Advances on Hormones in Cosmetics: Illegal Addition Status, Sample Preparation, and Detection Technology

Owing to the rapid development of the cosmetic industry, cosmetic safety has become the focus of consumers' attention. However, in order to achieve the desired effects in the short term, the illegal addition of hormones in cosmetics has emerged frequently, which could induce skin problems and even skin cancer after long-term use. Therefore, it is of great significance to master the illegal addition in cosmetics and effectively detect the hormones that may exist in cosmetics. In this review, we analyze the illegally added hormone types, detection values, and cosmetic types, as well as discuss the hormone risks in cosmetics for human beings, according to the data in unqualified cosmetics in China from 2017 to 2022. Results showed that although the frequency of adding hormones in cosmetics has declined, hormones are still the main prohibited substances in illegal cosmetics, especially facial masks. Because of the complex composition and the low concentration of hormones in cosmetics, it is necessary to combine efficient sample preparation technology with instrumental analysis. In order to give the readers a comprehensive overview of hormone analytical technologies in cosmetics, we summarize the advanced sample preparation techniques and commonly used detection techniques of hormones in cosmetics in the last decade (2012-2022). We found that ultrasound-assisted extraction, solid phase extraction, and microextraction coupled with chromatographic analysis are still the most widely used analytical technologies for hormones in cosmetics. Through the investigation of market status, the summary of sample pretreatment and detection technologies, as well as the discussion of their development trends in the future, our purpose is to provide a reference for the supervision of illegal hormone residues in cosmetics.

Multi-magnetic center ionic liquids for dispersive liquid-liquid microextraction coupled with in-situ decomposition based back-extraction for the enrichment of parabens in beverage samples

In this paper, several new multi-magnetic center magnetic ionic liquids (MMILs) were prepared with paramagnetic component simultaneously contained in both the cation and anion and used as extractants to establish a dispersive liquid-liquid microextraction (DLLME) approach followed by in-situ MMIL decomposition based back-extraction for the enrichment and determination of four parabens in beverages. The appropriate MMIL was selected by investigating the extraction performances of the obtained MMILs combined with high performance liquid chromatography-ultraviolet detection (HPLC-UV), and some other experimental factors were explored. Under the optimized DLLME conditions, the four parabens exhibited coefficients of determination (R²) above 0.9987 in the linear range of 0.1-500 ng·mL^-1 for ethylparaben, propylparaben and butylparaben and 0.2-500 ng·mL^-1 for methylparaben. The limits of detection (LODs) and limits of quantification (LOQs) were respectively within 0.03-0.06 ng·mL^-1 and 0.1-0.2 ng·mL^-1, and the relative standard deviations (RSDs) for intra-day and inter-day precision were below 10.8%. Moreover, the application of the developed MMIL-based DLLME method in beverage samples exhibited recoveries within 81.3%-112.1% with RSDs of 0.3%-13.1% at three different spiked levels.

A new magnetic ionic liquid based salting-out assisted dispersive liquid-liquid microextraction for the determination of parabens in environmental water samples

In this study, a new magnetic ionic liquid (MIL) was designed and prepared, containing a magnetic cation from the ligand N,N-dimethyl biguanide (DMBG) complexing with magnetic center Co²⁺ and a bis-trifluoromethanesulfonimide (NTf₂^-) anion. Using the MIL as the extraction solvent, a salting-out assisted dispersive liquid-liquid microextraction (SA-DLLME) combined with high performance liquid chromatography-ultraviolet detection (HPLC-UV) was established for the enrichment and detection of four parabens in environmental water samples. The one-factor-at-a-time experiment was employed to optimize the conditions affecting the extraction efficiency. Under the optimized extraction conditions, the limits of quantification (LOQs) of the four target analytes ranged from 2.0 ng mL^-1 to 2.8 ng mL^-1, and the coefficients of determination (R²) were above 0.9996 in the linear range of 2.8-400 ng mL^-1. On the other hand, the method displayed good repeatability and accuracy with intra-day and inter-day relative standard deviations (RSDs) of 2.1-13.0% and recoveries of 82.0-114.6%. The established method was applied to real samples with recoveries within 81.6-125.4%, and the results demonstrated that the method was practical.

Research Advances in the Analysis of Estrogenic Endocrine Disrupting Compounds in Milk and Dairy Products

Milk and dairy products are sources of exposure to estrogenic endocrine disrupting compounds (e-EDCs). Estrogenic disruptors can accumulate in organisms through the food chain and may negatively affect ecosystems and organisms even at low concentrations. Therefore, the analysis of e-EDCs in dairy products is of practical significance. Continuous efforts have been made to establish effective methods to detect e-EDCs, using convenient sample pretreatments and simple steps. This review aims to summarize the recently reported pretreatment methods for estrogenic disruptors, such as solid-phase extraction (SPE) and liquid phase microextraction (LPME), determination methods including gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS), Raman spectroscopy, and biosensors, to provide a reliable theoretical basis and operational method for e-EDC analysis in the future.

Ionic Liquid-Assisted DLLME and SPME for the Determination of Contaminants in Food Samples

Developing effective and green methods for food analysis and separation has become an urgent issue regarding the ever-increasing concern of food quality and safety. Ionic liquids (ILs) are a new chemical medium and soft functional material developed under the framework of green chemistry and possess many unique properties, such as low melting points, low-to-negligible vapor pressures, excellent solubility, structural designability and high thermal stability. Combining ILs with extraction techniques not only takes advantage of ILs but also overcomes the disadvantages of traditional extraction methods. This subject has attracted intensive research efforts recently. Here, we present a brief review of the current research status and latest developments regarding the application of IL-assisted microextraction, including dispersive liquid–liquid microextraction (DLLME) and solid-phase microextraction (SPME), in food analysis and separation. The practical applications of ILs in determining toxic and harmful substances in food specimens with quite different natures are summarized and discussed. The critical function of ILs and the advantages of IL-based microextraction techniques over conventional extraction techniques are discussed in detail. Additionally, the recovery of ILs using different approaches is also presented to comply with green analytical chemistry requirements.

A magnetic ionic liquid based vortex-assisted dispersive liquid-liquid microextraction coupled with back-extraction for the enrichment of fluoroquinolone antibiotics

In the present work, a magnetic ionic liquid (MIL) ([Co(DMBG)₂][Co(hfaca)₃]) was designed and synthesized with both the cation and anion respectively containing a paramagnetic component. With the prepared MIL as the extraction solvent, a vortex-assisted dispersive liquid-liquid microextraction (VA-DLLME) method was developed and combined with back-extraction for the enrichment of five fluoroquinolone antibiotics (FQs). The MIL can be easily collected and separated from the aqueous phase under an external magnetic field due to the strong magnetic susceptibility and red color. Some experimental factors affecting the extraction efficiency were investigated, and the optimum extraction efficiency was obtained in a basic solution (pH=9) for the extraction process and with 2% (v/v) formic acid as the back-extraction solvent. Under the optimized extraction and back-extraction conditions, the proposed method was validated and exhibited good linearity with coefficients of determination (R²) above 0.9956 in the range of 2.5-800 ng·mL^-1 and 5.0-800 ng·mL^-1, low limits of detection (LODs) within 0.75-1.5 ng·mL^-1 and satisfactory intra-day and inter-day precisions with relative standard deviations (RSDs) respectively less than 10.6% and 8.6%. Finally, the method was applied for the determination of five FQs in four samples of tap water, milk, honey and chicken, and good precision with RSDs of 0.5-9.5% and acceptable recoveries (73.8-114.3%) were obtained.

Preparation of Magnetic Metal-Organic Frameworks@Molecularly Imprinted Nanoparticles for Specific Extraction and Enrichment of Bisphenol A in Food

Metal-organic frameworks (MOFs) with systematically tailored structures have been suggested as promising precursors to the preparation of diverse functional materials. Herein, a facile and versatile layer-by-layer strategy without any special surface modifications has been proposed for the preparation of magnetic metal-organic frameworks (MMOFs) supported molecularly imprinted polymer nanoparticles (MMOFs@MIP), which are based on a magnetically susceptible core conjugated with an imidazole-derived self-assembled layer and a silane-based imprinted shell. The obtained MMOFs@MIPs, which integrated the advantages of Fe₃O₄, MOFs, and MIPs, were characterized and exhibited good magnetic properties, a rapid mass transfer rate, and an excellent adsorption selectivity as well as capacity for the targeted molecular - bisphenol A (BPA). Moreover, the MMOFs@MIPs were employed as adsorbents in magnetic solid phase extraction (MSPE) to selectively bind and rapidly separate BPA from real samples with satisfactory recoveries ranging from 88.3% to 92.3%. More importantly, the desirable reusability of MMOFs@MIP was also evaluated, and the recoveries still maintained above 88.0% even after five re-use cycles. Furthermore, combined with high-performance liquid chromatography (HPLC) analysis, a novel MSPE-HPLC method was developed, enabling the highly selective and sensitive detection of BPA in a wide linear range of 0.5–5000 μg L⁻¹ with a low limit of detection (LOD) of 0.1 μg L⁻¹. This work contributes a promising method for constructing various functional nanoparticles @MOFs@MIP hybrid materials for applications in many different fields.

Fabrication of Magnetic Al-Based Fe3O4@MIL-53 Metal Organic Framework for Capture of Multi-Pollutants Residue in Milk Followed by HPLC-UV

The efficient capture of multi-pollutant residues in food is vital for food safety monitoring. In this study, in-situ-fabricated magnetic MIL-53(Al) metal organic frameworks (MOFs), with good magnetic responsiveness, were synthesized and applied for the magnetic solid-phase extraction (MSPE) of chloramphenicol, bisphenol A, estradiol, and diethylstilbestrol. Terephthalic acid (H₂BDC) organic ligands were pre-coupled on the surface of amino-Fe₃O₄ composites (H₂BDC@Fe₃O₄). Fe₃O₄@MIL-53(Al) MOF was fabricated by in-situ hydrothermal polymerization of H₂BDC, Al (NO₃)₃, and H₂BDC@Fe₃O₄. This approach highly increased the stability of the material. The magnetic Fe₃O₄@MIL-53(Al) MOF-based MSPE was combined with high-performance liquid chromatography-photo diode array detection, to establish a novel sensitive method for analyzing multi-pollutant residues in milk. This method showed good linear correlations, in the range of 0.05–5.00 μg/mL, with good reproducibility. The limit of detection was 0.004–0.108 μg/mL. The presented method was verified using a milk sample, spiked with four pollutants, which enabled high-throughput detection and the accuracies of 88.17–107.58% confirmed its applicability, in real sample analysis.

A Gadolinium-Based Magnetic Ionic Liquid for Supramolecular Dispersive Liquid-Liquid Microextraction Followed by HPLC/UV for Determination of Favipiravir in Human Plasma

Favipiravir is a potential antiviral medication that has been recently licensed for COVID-19 treatment. In this work, a gadolinium based magnetic ionic liquid was prepared and used as an extractant in dispersive liquid-liquid microextraction (DLLME) of favipiravir in human plasma. The high enriching ability of DLLME allowed determination of favipiravir in real samples using HPLC/UV with sufficient sensitivity. The effects of several variables on extraction efficiency were investigated, including type of extractant, amount of extractant, type of disperser and disperser volume. The maximum enrichment was attained using 50mg of the Gd-MIL and 150μL of tetrahydrofuran. The Gd-based MIL could form a supramolecular assembly in the presence of tetrahydrofuran, which enhanced the extraction efficiency of favipiravir. The developed method was validated according to FDA bioanalytical method validation guidelines. The coefficient of determination was found to be 0.9999, for a linear concentration range of 25 to 1.0 × 10⁵ ng/mL. The percent recovery (accuracy) varied from 99.83 to 104.2 %, with % RSD values (precision) ranging from 4.07 to 11.84 %. Total extraction time was about 12 min and the HPLC analysis time was 5 min. The method was found simple, selective and sensitive for determination of favipiravir in real human plasma.

An overview of magnetic ionic liquids: From synthetic strategies to applications in microextraction techniques

Remarkable progress has been achieved in the application of magnetic ionic liquids in microextraction-based procedures. These materials exhibit unique physicochemical properties of ionic liquids featuring additional responses to magnetic fields by incorporating a paramagnetic component within the chemical structure. This intriguing property can open new horizons in analytical extractions because the solvent manipulation is facilitated. Moreover, the tunable chemical structures of magnetic ionic liquids also allow for task-specific extractions that can significantly increase the method selectivity. This review aimed at providing an up-to-date overview of articles involving synthesis, physicochemical properties, and applications of magnetic ionic liquids highlighting recent developments and configurations. Moreover, a section containing critical evaluation and future trends in magnetic ionic liquid-based extractions is included.

Magnetic Ionic Liquids in Sample Preparation: Recent Advances and Future Trends

In the last decades, a myriad of materials has been synthesized and utilized for the development of sample preparation procedures. The use of their magnetic analogues has gained significant attention and many procedures have been developed using magnetic materials. In this context, the benefits of a new class of magnetic ionic liquids (MILs), as non-conventional solvents, have been reaped in sample preparation procedures. MILs combine the advantageous properties of ionic liquids along with the magnetic properties, creating an unsurpassed combination. Owing to their unique nature and inherent benefits, the number of published reports on sample preparation with MILs is increasing. This fact, along with the many different types of extraction procedures that are developed, suggests that this is a promising field of research. Advances in the field are achieved both by developing new MILs with better properties (showing either stronger response to external magnetic fields or tunable extractive properties) and by developing and/or combining methods, resulting in advanced ones. In this advancing field of research, a good understanding of the existing literature is needed. This review aims to provide a literature update on the current trends of MILs in different modes of sample preparation, along with the current limitations and the prospects of the field. The use of MILs in dispersive liquid–liquid microextraction, single drop microextraction, matrix solid-phase dispersion, etc., is discussed herein among others.

Recent Advances in Sample Preparation for Cosmetics and Personal Care Products Analysis

The use of cosmetics and personal care products is increasing worldwide. Their high matrix complexity, together with the wide range of products currently marketed under different forms imply a challenge for their analysis, most of them requiring a sample pre-treatment step before analysis. Classical sample preparation methodologies involve large amounts of organic solvents as well as multiple steps resulting in large time consumption. Therefore, in recent years, the trends have been moved towards the development of simple, sustainable, and environmentally friendly methodologies in two ways: (i) the miniaturization of conventional procedures allowing a reduction in the consumption of solvents and reagents; and (ii) the development and application of sorbent- and liquid-based microextraction technologies to obtain a high analyte enrichment, avoiding or significantly reducing the use of organic solvents. This review provides an overview of analytical methodology during the last ten years, placing special emphasis on sample preparation to analyse cosmetics and personal care products. The use of liquid–liquid and solid–liquid extraction (LLE, SLE), ultrasound-assisted extraction (UAE), solid-phase extraction (SPE), pressurized liquid extraction (PLE), matrix solid-phase extraction (MSPD), and liquid- and sorbent-based microextraction techniques will be reviewed. The most recent advances and future trends including the development of new materials and green solvents will be also addressed.

Membrane-protected covalent organic framework fiber for direct immersion solid-phase microextraction of 17beta-estradiol in milk

17beta-estradiol (E2) could accumulate in human body through milk and cause various diseases by interfering with the endocrine system. Herein, we coated stainless steel wire with covalent organic framework LZU1 (COF-LZU1) and Nafion protected by dialysis membrane for direct immersion solid phase microextraction (DI-SPME) and coupled with gas chromatography-flame ionization detection (GC-FID) for the detection of trace E2 in milk samples. With dialysis membrane protection, the stability of SPME fiber was improved and the extraction efficiency was only reduced by 7% after repeated use of 160 times. The extraction efficiency of E2 with the home-made fiber COF-LZU1 was 22.1, 8.4, 3.6 times higher than that of bare stainless steel wire, PDMS/DVB and PDMS, respectively. The method had been successfully applied to milk samples, and the relative recoveries were between 77.27% and 108.26%. It can provide an effective and general method for the pretreatment of complex matrix samples.

High-throughput approach for the in situ generation of magnetic ionic liquids in parallel-dispersive droplet extraction of organic micropollutants in aqueous environmental samples

In this work, a novel and high-throughput parallel-dispersive droplet extraction (Pa-DDE) based on in situ formation of the hydrophobic MILs ([Co(C₄IM)₄⁺²]2[NTf₂^-], [Ni(C₄IM)₄⁺²]2[NTf₂^-] and [Ni(BeIM)₄⁺²]2[NTf₂^-]) is demonstrated, for the first time, for the determination of benzophenone, metolachlor, triclocarban, pendimethalin, 4-methylbenzylidene camphor, and 2-ethylhexyl-4-methoxycinnamate from aqueous environmental samples. This experimental setup is comprised of a 96-well plate system containing a set of magnetic pins which were used to collect the MIL droplet after in situ formation. This consolidated system enabled simultaneous extraction of up to 96 samples and MIL production in one step. Using this apparatus, sample preparation times of 0.78 min per sample was achieved. The experimental conditions were carefully optimized using uni and multivariate approaches. The optimal conditions were comprised of sample volume of 1.25 mL, 4 mg of [Co(C₄IM)₄⁺²]2[Cl^-] and 40 μL of LiNTf₂ for the in situ formation, and dilution in 20 μL of acetonitrile. The analytical parameters of merit were successfully determined with LODs ranging from 7.5 to 25 μg L^-1 and coefficients of determination higher than 0.989. Intraday and interday precision ranged from 6.4 to 20.6% (n = 3) and 11.6-22.9% (n = 9), respectively, with analyte relative recovery ranging between 53.9 and 129.1%.

Efficient Low-Cost Procedure for Microextraction of Estrogen from Environmental Water Using Magnetic Ionic Liquids

In this study, three magnetic ionic liquids (MILs) were investigated for extraction of four estrogens, i.e., estrone (E1), estradiol (E2), estriol (E3), and ethinylestradiol (EE2), from environmental water. The cation trihexyl(tetradecyl)phosphonium ([P₆₆₆₁₄]⁺), selected to confer hydrophobicity to the resulting MIL, was combined with tetrachloroferrate(III), ferricyanide, and dysprosium thiocyanate to yield ([P₆₆₆₁₄][FeCl₄]), ([P₆₆₆₁₄]₃[Fe(CN)₆]), and ([P₆₆₆₁₄]₅[Dy(SCN)₈]), respectively. After evaluation of various strategies to develop a liquid–liquid microextraction technique based on synthesized MILs, we placed the MILs onto a magnetic stir bar and used them as extracting solvents. After extraction, the MIL-enriched phase was dissolved in methanol and injected into an HPLC–UV for qualitative and quantitative analysis. An experimental design was used to simultaneously evaluate the effect of select variables and optimization of extraction conditions to maximize the recovery of the analytes. Under optimum conditions, limits of detection were in the range of 0.2 (for E3 and E2) and 0.5 μg L⁻¹ (for E1), and calibration curves exhibited linearity in the range of 1–1000 μg L⁻¹ with correlation coefficients higher than 0.998. The percent relative standard deviation (RSD) was below 5.0%. Finally, this method was used to determine concentration of estrogens in real lake and sewage water samples.

Synthesis of magnetic metal organic framework/covalent organic framework hybrid materials as adsorbents for magnetic solid-phase extraction of four endocrine-disrupting chemicals from milk samples

RATIONALE

Endocrine-disrupting chemicals (EDCs), widespread and easily ingested through the simple food chain, have been suggested to pose potential carcinogenic threats to human health. Considering food safety and public health, it is urgent to establish a sensitive and effective method to enrich and determine EDCs in food samples.

METHODS

Novel hybrid nanocomposites Fe₃ O₄ @A-TpBD@NH₂ -MIL-125(Ti) were synthesized through the formation of amide bonds. The as-prepared Fe₃ O₄ were innovatively encapsulated with 4-aminobenzoic acid functionalized COF(A-TpBD) to generate bare carboxyl (-COOH), which formed amide bonds with the NH₂ -MIL-125(Ti), generating well-defined and hierarchical hybrid materials. The Fe₃ O₄ @A-TpBD@NH₂ -MIL-125(Ti) materials were used as the adsorbents for magnetic solid-phase extraction (MSPE) coupled with high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) to enrich and determine EDCs (E1, E2, E3 and BPA) from milk samples.

RESULTS

Fe₃ O₄ @A-TpBD@NH₂ -MIL-125(Ti) exhibited improved adsorption efficiency and selectivity based on π-π stacking interaction, hydrogen bonding, electrostatic interaction, and the interaction between the hydroxyl group in EDCs and titanium ions (IV, [Ti]⁴⁺ ). Under the optimized conditions, Fe₃ O₄ @A-TpBD@NH₂ -MIL-125(Ti)-based MSPE coupled with HPLC/MS/MS showed good linearity with correlation coefficient (R² ) ≥0.9983 and high sensitivity with limits of detection (LODs) in the range of 0.37-0.85 μg/L. Moreover, the developed method was successfully employed to detect EDCs in milk samples.

CONCLUSIONS

Fe₃ O₄ @A-TpBD@NH₂ -MIL-125(Ti) possess good adsorption capability and selectivity for EDCs. In addition, the proposed MSPE-HPLC/MS/MS method based on Fe₃ O₄ @A-TpBD@NH₂ -MIL-125(Ti) is effective and sensitive for the determination of EDCs in real samples, which can be used as a robust alternative method to monitor EDCs in complex matrices.

A gadolinium-based magnetic ionic liquid for dispersive liquid-liquid microextraction

A hydrophobic gadolinium-based magnetic ionic liquid (MIL) was investigated for the first time as an extraction solvent in dispersive liquid–liquid microextraction (DLLME). The tested MIL was composed of trihexyl(tetradecyl)phosphonium cations and paramagnetic gadolinium chloride anions. The prepared MIL showed low water miscibility, reasonable viscosity, markedly high magnetic susceptibility, adequate chemical stability, low UV background, and compatibility with reversed-phase HPLC solvents. These features resulted in a more efficient extraction than the corresponding iron or manganese analogues. Accordingly, the overall method sensitivity and reproducibility were improved, and the analysis time was reduced. The applicability of the proposed MIL was examined through the microextraction of four sartan antihypertensive drugs from aqueous samples followed by reversed-phase HPLC with UV detection at 240 nm. The DLLME procedures were optimized for disperser solvent type, MIL mass, disperser solvent volume, as well as acid, base, and salt addition. The limits of quantitation (LOQs) obtained with the analysis of 1.2-mL samples after DLLME and HPLC were 80, 30, 40, and 160 ng/mL for azilsartan medoxomil, irbesartan, telmisartan, and valsartan, respectively. Correlation coefficients were greater than 0.9988 and RSD values were in the range of 2.48–4.07%. Under the optimized microextraction conditions and using a 5-mL sample volume, enrichment factors were raised from about 40 for all sartans using a 1.2-mL sample to 175, 176, 169, and 103 for azilsartan medoxomil, irbesartan, valsartan, and telmisartan, respectively. The relative extraction recoveries for the studied sartans in river water varied from 82.5 to 101.48% at a spiked concentration of 0.5 μg/mL for telmisartan and irbesartan and 1 μg/mL for azilsartan medoxomil and valsartan.

Recent Progress on Luminescent Metal-Organic Framework-Involved Hybrid Materials for Rapid Determination of Contaminants in Environment and Food

The high speed of contaminants growth needs the burgeoning of new analytical techniques to keep up with the continuous demand for monitoring and legislation on food safety and environmental pollution control. Metal-organic frameworks (MOFs) are a kind of advanced crystal porous materials with controllable apertures, which are self-assembled by organic ligands and inorganic metal nodes. They have the merits of large specific surface areas, high porosity and the diversity of structures and functions. Latterly, the utilization of metal-organic frameworks has attracted much attention in environmental protection and the food industry. MOFs have exhibited great value as sensing materials for many targets. Among many sensing methods, fluorometric sensing is one of the widely studied methods in the detection of harmful substances in food and environmental samples. Fluorometric detection based on MOFs and its functional materials is currently one of the most key research subjects in the food and environmental fields. It has gradually become a hot research direction to construct the highly sensitive rapid sensors to detect harmful substances in the food matrix based on metal-organic frameworks. In this paper, we introduced the synthesis and detection application characteristics (absorption, fluorescence, etc.) of metal-organic frameworks. We summarized their applications in the MOFs-based fluorometric detection of harmful substances in food and water over the past few years. The harmful substances mainly include heavy metals, organic pollutants and other small molecules, etc. On this basis, the future development and possible application of the MOFs have prospected in this review paper.