Recent advances of ionic liquids in sample preparation

Recent advance on microextraction sampling technologies for bioanalysis

The contents of target substances in biological samples are usually at low concentration levels, and the matrix of biological samples is usually complex. Sample preparation is considered a very critical step in bioanalysis. At present, the utilization of microextraction sampling technology has gained considerable prevalence in the realm of biological analysis. The key developments in this field focus on the efficient microextraction media and the miniaturization and automation of adaptable sample preparation methods currently. In this review, the recent progress on the microextraction sampling technologies for bioanalysis has been introduced from point of view of the preparation of microextraction media and the microextraction sampling strategies. The advance on the microextraction media was reviewed in detail, mainly including the aptamer-functionalized materials, molecularly imprinted polymers, carbon-based materials, metal-organic frameworks, covalent organic frameworks, etc. The advance on the microextraction sampling technologies was summarized mainly based on in-vivo sampling, in-vitro sampling and microdialysis technologies. Moreover, the current challenges and perspective on the future trends of microextraction sampling technologies for bioanalysis were briefly discussed.

Development of Cholinium-Based API Ionic Liquids with Enhanced Drug Solubility: Biological Evaluation and Interfacial Properties

We report an efficient sustainable two-step anion exchange synthetic procedure for the preparation of choline API ionic liquids (Cho-API-ILs) that contain active pharmaceutical ingredients (APIs) as anions combined with choline-based cations. We have evaluated the in vitro cytotoxicity for the synthesized compounds using three different cells lines, namely, HEK293 (normal kidney cell line), SW480, and HCT 116 (colon carcinoma cells). The solubility of APIs and Cho-API-ILs was evaluated in water/buffer solutions and was found higher for Cho-API-ILs. Further, we have investigated the antimicrobial potential of the pure APIs, ILs, and Cho-API-ILs against clinically relevant microorganisms, and the results demonstrated the promise of Cho-API-ILs as potent antimicrobial agents to treat bacterial infections. Moreover, the aggregation and adsorption properties of the Cho-API-ILs were observed by using a surface tension technique. The aggregation behavior of these Cho-API-ILs was further supported by conductivity and pyrene probe fluorescence. The thermodynamics of aggregation for Cho-API-ILs has been assessed from the temperature dependence of surface tension. The micellar size and their stability have been studied by dynamic light scattering, transmission electron microscopy, and zeta potential. Therefore, the duality in the nature of Cho-API-ILs has been explored with the upgradation of their physical, chemical, and biopharmaceutical properties, which enhance the opportunities for advances in pharmaceutical sciences.

Simple, fast and eco-friendly micro-solid phase extraction based on thiol and ionic liquid bi-functional nanofibers membrane for the determination of sulfonamides in environmental water

BACKGROUND

Sulfonamides (SAs) are a class of synthetic antibacterial agents that are diffusely used in the medical industry and animal husbandry. Their prevalence in the influents and effluents of water treatment plants, as well as in rivers and groundwater, has provoked worldwide concern. Monitoring SAs in environmental water is of great significance for public health. However, most of the available detection techniques for SAs are cumbersome and time-consuming. With the increasing number of actual samples, simple, fast and environmentally friendly analytical methods are always in demand.

RESULTS

Herein, we describe a highly efficient micro-solid phase extraction (μ-SPE) sample preparation technique based on a novel thiol and ionic liquid bi-functional nanofibers membrane (IL-SH-PAN NFsM) for multi-residue detection of sulfonamides (SAs) in water samples. By the synergistic effect of -SH and -IL, the as-prepared IL-SH-PAN NFsM demonstrated high adsorption capacity and excellent selectivity for SAs. The water samples can be directly used for μ-SPE without pH and ionic strength adjustment, and the eluent can be directly collected for HPLC-MS/MS analysis. Compared with other methods reported in the literature, this method required much shorter extraction time (2 min for a batch), much less amount of adsorbent (4.0 mg) and organic solvent (0.5 mL), while providing much higher sensitivity (1.4-3.9 ng L-1), and fine recoveries (88.8%-117.7%) with relative standard deviations less than 4.26%.

SIGNIFICANCE AND NOVELTY

A bi-functional nanofibers membrane was prepared for efficient extraction of SAs. The adsorbent exhibited superior adsorption performance and excellent selectivity. The underlying interaction mechanisms derived from -SH and -IL were proposed, which provide a new idea for preparing versatile adsorbents. Rapid, efficient and sensitive detection of SAs in water was achieved. The novel sample preparation technique can be expected as an efficient method for routine trace SAs residue monitoring in various water samples.

An effervescence-assisted microextraction for parabens in foodstuffs based on deep eutectic solvent composed of methyltrioctyl ammonium chloride and decanoic acid

An efficient and ecofriendly effervescence-assisted emulsification microextraction approach based on hydrophobic deep eutectic solvent (EA-EME-DES) was developed for the sensitive chromatographic determination of parabens (i.e., methyl-, ethyl-, propyl- and butylparaben) in foodstuffs. The DES extractant consisted of methyltrioctyl ammonium chloride (MTAC) and decanoic acid (DecA) (1:3, mol/mol), and had high hydrophobicity, solubility and stability. During the microextraction procedure, sodium carbonate was introduced to facilitate the dissolution of parabens in aqueous solution, DES dispersion and phase separation by enhancing solution pH and generating CO2 bubbles. The developed method exhibited satisfactory linearity (R2 ≥ 0.9986), detection limits (0.01-0.03 μg/g), quantitation limits (0.04-0.09 μg/g), recoveries (87.8% to 111%, with RSDs of 0.8% to 5%) and negligible matrix effects, hence it had remarkable effectiveness and applicability in determining parabens in complex foodstuffs.

Biomarkers in psychiatric disorders

Psychiatric disorders represent a significant socioeconomic and healthcare burden worldwide. Of these, schizophrenia, bipolar disorder, major depressive disorder and anxiety are among the most prevalent. Unfortunately, diagnosis remains problematic and largely complicated by the lack of disease specific biomarkers. Accordingly, much research has focused on elucidating these conditions to more fully understand underlying pathophysiology and potentially identify biomarkers, especially those of early stage disease. In this chapter, we review current status of this endeavor as well as the potential development of novel biomarkers for clinical applications and future research study.

Separation and purification of glycosides from medicinal plants based on strong polar separation medium with online closed-loop mode

Natural glycosides widely distributed in medicinal plants are valuable sources of therapeutic agents, showing various pharmacological effects. The separation and purification of natural glycosides are meaningful for their pharmacological research, which face with great challenges due to the complex of medicinal plants samples. In this work, two kinds of functional monolithic separation mediums A and S were fabricated and fully applied in the online extraction, separation and purification of active glycoside components from medicinal plants with a simple-procedure closed-loop mode. Chrysophanol glucoside and physcion glucoside were detected and separated from Rhei Radix et Rhizoma using separation medium A as a solid-phase extraction adsorbent. Rhapontin was isolated and purified from Rheum hotaoense C. Y. Cheng et Kao using separation medium S as the stationary phase of high-performance liquid chromatography. Compared to the reported literatures, high yield of 5.68, 1.20 and 4.76 mg g-1 of these three products were obtained with high purity. These two online closed-loop mode methods were carried out using high-performance liquid chromatography system, in which the sample injection, isolation and purification procedures are all online mode, and reduced loss compared to offline extraction and purification procedures, thus achieving high recovery and high purity.

Simultaneous determination of multiple mycotoxins in corn and wheat by high efficiency extraction and purification based on polydopamine and ionic liquid bifunctional nanofiber mat

Due to the universality and harmfulness of mycotoxin co-contamination in cereals, it is of great significance to simultaneously monitor various mycotoxins co-polluted to ensure food safety and public health. In this work, a nanofiber mat modified by polydopamine and ionic liquid (PDA-IL-NFsM) was prepared and utilized as a solid-phase extraction (SPE) adsorbent for the simultaneous quantitative detection of multiple mycotoxins in corn and wheat. The PDA-IL-NFsM can form multiple retention mechanisms with the targets through hydrogen bond, π-π interaction, electrostatic or hydrophobic interaction, it shows favorable simultaneous adsorption performance (adsorption efficiency mostly higher than 88.27%) for fifteen mycotoxins in seven classes. Moreover, it can significantly reduce the matrix effect (lower than -13.69%), showing a good purification effect on the sample matrix. Based on the superior performance of PDA-IL-NFsM, a simple sample preparation method was established. The sample extract is simply diluted with water for SPE, and the eluent can be directly collected for ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) analysis. The detection limit can reach 0.04-4.21 μg kg^-1, the recovery was 80.09%-113.01%, and the relative standard deviations of intra-day and inter-day precision were 2.80%-14.81% and 0.68%-13.80% respectively. The results show that the proposed method has good sensitivity, accuracy and precision, and has practical application potential.

Thermodynamic characterization of interactions between environmental contaminants and room temperature ionic liquids using static headspace gas chromatography with vacuum ultraviolet detection

Understanding the thermodynamic interactions between an analyte and the sample phase is of paramount importance when choosing a co-solvent in headspace analysis. A sample phase - gas phase equilibrium partition coefficient (Kp) is used fundamentally to describe the distribution of the analyte between the two phases. Kp determinations by headspace gas chromatography (HS-GC) were acquired by two methods: vapor phase calibration (VPC) and phase ratio variation (PRV). Here, we demonstrated a pressurized - loop headspace system in conjunction with gas chromatography vacuum ultraviolet detection (HS-GC-VUV) to directly calculate the concentration of analytes in the gas phase from room temperature ionic liquids (RTILs) sample phases, using pseudo-absolute quantification (PAQ). PAQ, an attribute of VUV detection, allowed for quick determination of Kp and other thermodynamic properties, such as enthalpy (ΔH) and entropy (ΔS) of the system through the use of van't Hoff plots in the temperature range of 70-110 °C. The Kp determinations by PAQ were comparable to those obtained using the VPC method with percent difference ranging from ≤ 1-33%. Kp determinations were made for analytes (cyclohexane, benzene, octane, toluene, chlorobenzene, ethylbenzene, m-,p-, and o-xylene) at the varying temperatures (70-110 °C) using different RTILs (1-ethyl-3-methylimidazolium ethylsulfate ([EMIM][ESO₄]), 1-ethyl-3-methylimidazolium diethylphosphate ([EMIM][DEP]), and tris(2-hydroxyethyl)methylammonium methylsulfate ([MTEOA][MeOSO₃])) and (1-ethyl-3-methylimidazolium bis(trisfluoromethanesulfonyl)imide ([EMIM] [NTF₂])). The results from the van't Hoff analysis revealed that [EMIM] cation-based RTILs exhibit strong solute-solvent interactions with analytes that have π- electrons.

Application of imidazolium based ionic liquids grafted on microcrystalline cellulose as demulsifiers for water in crude oil (W/O) emulsions

Separation of water and oil from water-in-oil (W/O) emulsion before transportation and refining is very important and critical. Ionic liquids (ILs) and their derivatives have recently attracted much attention as efficient chemical agents for breaking emulsions. So, here, a series of microcrystalline cellulose (MCC) grafted with imidazolium-based ionic liquids (IM-ILs) were synthesized, named as MCC@IM-ILs, and evaluated as eco-friendly surface-active agents for the separation of water from the crude oil. Structure of the synthesized compounds was confirmed by different characterization techniques. Dehydration efficiency percent (DE%) of the synthesized demulsifiers was measured and compared with each other. Synthesized MCC@IM-ILs showed an acceptable DE% to demulsify three kinds of W/O emulsions with different water content after 5 min. Concentration, alkyl chain length, and counter-anion of the synthesized MCC@IM-ILs play a key role in separating water from crude oil. Demulsifier with C10 alkyl chain length showed better DE% than the corresponding demulsifier with C6 alkyl chain length in the W/O (30:70 v/v) emulsion. Also, demulsifier with Br counter anion showed lower DE% than the corresponding BF₄ ion-exchanged compound with higher hydrophilicity. Synthesized demulsifiers immobilized on ILs have significant advantages compared to unsupported ILs due to the use of green and economical cellulosic substrate.

Rapid determination of ampyra in urine samples using dispersive liquid-liquid microextraction coupled with ion mobility spectrometry

Ampyra (AMP, 4-Aminopyridine) is a potassium channel blocker that attracts growing research interest due to its adverse effects at high doses. The fast analysis of AMP is challenging because it typically requires complex analytical techniques. In this research, we developed and validated a novel method to assess the fast and quantitative analysis of AMP from real samples. This method combines the strength of ion mobility spectrometry (IMS) for rapid detection and the dispersive liquid-liquid microextraction as a fast and effective preconcentration method for the preconcentration/extraction of AMP. In this method, Ag nanoparticles were used as modifier agents. Moreover, the proposed mechanism for interaction of AMP with AgNPs was investigated based on the quantum theory of atoms in molecules (QTAIM) analysis. Also, the sensitivity of the proposed method was improved through the application of a delay on the carrier gas flow after sample injection. Under the optimum conditions, the developed method detected AMP in the linear range of 0.4-16 μmol L^-1 with a detection limit of 0.12 µmol L^-1. Finally, the developed method was successfully employed to quantify AMP in urine samples. Method validation was performed by comparing our results with those obtained by HPLC-UV/Vis, confirming the applicability of the proposed method for the AMP analysis in real samples. The proposed method will open up a new door toward developing simple, fast, and effective analytical methods.

Ionic Liquid-Dispersive Micro-Extraction and Detection by High Performance Liquid Chromatography-Mass Spectrometry for Antifouling Biocides in Water

A simple analytical method was developed and evaluated for the determination of two antifouling biocides using an ionic liquid-dispersive liquid-liquid micro-extraction (IL-DLLME) and a high-performance liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) analysis. Irgarol 1051 and Sea-Nine 211 were extracted from deionized water, lake water, and seawater using IL 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIm][PF6]) and ethyl acetate as the extraction solvent and the dispersion solvent. Several factors were considered, including the type and volume of extraction and dispersive solvent, IL amount, sample pH, salt effect, and cooling temperature. The developed method resulted in a recovery range of 78.7-90.3%, with a relative standard deviation (RSD, n = 3) less than 7.5%. The analytes were enriched greater than 40-fold, and the limits of detection (LOD) for two antifouling biocides were 0.01-0.1 μg L^-1. The method was effectively applied for the analysis of real samples of freshwater as well as samples of seawater.

Designing an "all-in-one" microextraction capsule device for the liquid chromatographic-fluorescence determination of doxorubicin and its metabolites in rat plasma

In this study, an "all-in-one" microextraction device was designed and fabricated for the extraction of doxorubicin and its two metabolites from rat plasma prior to their determination by high performance liquid chromatography coupled to fluorescence detector. A sol-gel-based sorbent was synthesized in situ and incorporated within two conjoined porous polypropylene tubes together with a cylindrical magnetic bar in order to avoid the need of an external stirring bar. Among other sorbents investigated, the moderately polar sol-gel poly(tetrahydrofuran) was found to be advantageous due to its high affinity toward the target analytes. Systematic investigation of the critical parameters affecting the adsorption and the desorption step was carried out. Due to the "built-in" filtration mechanism of the porous microextraction capsules, the isolation of the analytes was performed directly in the plasma matrix without any previous sample pretreatment (i.e., protein precipitation, centrifugation, etc.). The proposed method was validated in terms of linearity, accuracy, precision, specificity, sensitivity, and stability according to the FDA guidelines. The limits of detection ranged between 1 - 2 ng mL^-1 while the lower limits of quantitation of the analytes were calculated as 10 ng mL^-1. The accuracy (% relative error) was found within -9.7 - 15.3% under both intra- and inter-day conditions. The precision was better than 13.4% in all cases. ComplexGAPI index was employed to present the green attributes of the developed protocol from the preparation of the microextraction device to the final determination of the analytes. Finally, the applicability of the fabricated stand-alone extraction device was demonstrated in the analysis of the target analytes in rat plasma after intravenous administration of doxorubicin in order to assess its pharmacokinetic profile.

Separation and Enrichment of Selected Polar and Non-Polar Organic Micro-Pollutants—The Dual Nature of Quaternary Ammonium Ionic Liquid

In this study, the dual nature of quaternary ammonium ionic liquid–didecyldimethylammonium perchlorate, [DDA][ClO4], was evaluated. A novel and sensitive in situ ionic liquid dispersive liquid–liquid microextraction method (in situ IL-DLLME) combined with magnetic retrieval (MR) was applied to enrich and separate selected organic micro-pollutants, both polar and non-polar. The magnetic support relied on using unmodified magnetic nanoparticles (MNPs) prepared by the co-precipitation of Fe2+/Fe3+ (Fe3O4). The separation technique was on-lined with high-performance liquid chromatography (HPLC–DAD) verified by inverse gas chromatography. An anion exchanger, NaClO4, was added to form an in situ hydrophobic IL. The fine droplets of [DDA][ClO4], molded in aqueous samples, functioned as an extractant for isolating the studied compounds. Then the carrier MNPs were added to separate the IL from the water matrix. The supernatant-free sample was desorbed in acetonitrile (MeCN) and injected into the HPLC system. The applicability of [DDA][ClO4] as an extraction solvent in the MR in situ IL-DLLME method was checked by the selectivity parameters (Sij∞) at infinite dilution. The detection limit (LOD) ranged from 0.011 to 0.079 µg L−1 for PAHs and from 0.012 to 0.020 µg L−1 for benzophenones. The method showed good linearity with correlation coefficients (r2) ranging from 0.9995 to 0.9999.

Ionic liquid-based magnetic nanoparticles for magnetic dispersive solid-phase extraction: A review

Due to their highly tunable nature and outstanding physicochemical properties, ionic liquids (ILs) have been widely reported for use in the synthesis of multitudinous magnetic nanoparticles (MNPs). IL-based magnetic nanoparticles (IL-MNPs) have great potential in magnetic dispersive solid-phase extraction (MDSPE). At present, IL-MNPs have been successfully applied in the pretreatment of MDSPE samples from medicines, pesticides, veterinary drugs, heavy metals, dyes, additives, and proteins in agricultural products, foods and beverages, environmental water, and biological samples. In this review, the preparation of IL-MNPs and their application in MDSPE are comprehensively summarized. The structural characteristics of the introduced ILs used to prepare the IL-MNPs and the synthetic routes employed to obtain the IL-MNPs are described, including physical coating and chemical bonding methods. The IL-MNPs are then classified and described according to different modified materials, including silica-based materials, carbon-based materials, metal-organic frameworks, molecularly imprinted polymers and other interesting large/small molecules. Finally, the research prospects and development directions of IL-MNPs in the context of MDSPE are further identified.

Sponge-like porous manganese(II, III) oxide as a coating for solvent-assisted solid-phase microextraction of polycyclic aromatic hydrocarbons followed by gas chromatography-mass spectrometry

A nanostructure sponge-like porous manganese(II, III) oxide was synthesized and applied as a new fiber coating for solvent-assisted solid-phase microextraction. The synthesized material was characterized via Fourier-transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, X-ray diffraction, and N₂ adsorption/desorption techniques. To investigate the extraction performance of the prepared material, direct immersion solid-phase microextraction followed by gas chromatography-mass spectrometry was used for the determination of the selected polycyclic aromatic hydrocarbons in wastewater samples. Three polycyclic aromatic hydrocarbons including 1-methylnaphthalene, anthracene, and pyrene were selected as model analytes. To maximize the sensitivity of the method, key experimental factors affecting the extraction efficiency of the analytes such as ionic strength, extraction solvent, stirring rate, extraction temperature and time, and desorption temperature and time were optimized. The applicability of the new coating material for the extraction of the selected analytes from wastewater samples was evaluated. Under the optimum conditions, detection limits between 0.7 and 1.5 ng L^-1 were obtained for the model analytes. The linear dynamic range was 5.0-3.0 × 10³ ng L^-1 for all the analytes. Relative standard deviations were between 2 and 11%. In the case of real sample analysis, the extraction recoveries of the analytes were obtained in the range of 77-111%.

Hybrid Materials Formed with Green Metal-Organic Frameworks and Polystyrene as Sorbents in Dispersive Micro-Solid-Phase Extraction for Determining Personal Care Products in Micellar Cosmetics

Hybrid materials based on polystyrene (PS) and green metal-organic frameworks (MOFs) were synthesized, characterized, and evaluated as potential sorbents in dispersive micro-solid-phase extraction (µ-dSPE). Among the resulting materials, the hybrid PS/DUT-67(Zr) was selected as the adequate extraction material for the monitoring of six personal care products in micellar cosmetic samples, combining the µ-dSPE method with ultra-high performance liquid chromatography (UHPLC) coupled to ultraviolet/visible detection (UV/Vis). Univariate studies and a factorial design were performed in the optimization of the microextraction procedure. The compromise optimum extraction conditions included 20 mg of PS/DUT-67(Zr) for 10 mL of sample, 2 min of extraction time, and two desorption steps using 100 µL of acetonitrile and 5 min assisted by vortex in each one. The validated μ-dSPE-UHPLC-UV/Vis method presented limits of detection and quantification down to 3.00 and 10.0 μg·L⁻¹, respectively. The inter-day precision values were lower than 23.5 and 21.2% for concentration levels of 75 μg·L⁻¹ and 650 μg·L⁻¹, respectively. The hydrophobicity of the resulting PS/DUT-67(Zr) material was crucial for the improvement of its extraction capacity in comparison with its unitary components, showing the advantages of combining MOFs with other materials, getting new sorbents with interesting properties.

Ionic Liquids as Components of Systems for Metal Extraction

This review addresses research and development on the use of ionic liquids as extractants and diluents in the solvent extraction of metals. Primary attention is given to the efficiency and selectivity of metal extraction from industrial wastewater with ionic liquids composed of various cations and anions. The review covers literature sources published in the period of 2010–2021. The bibliography includes 98 references dedicated to research on the extraction and separation of lanthanides (17 sources), actinides (5 sources), heavy metals (35 sources), noble metals, including the platinum group (16 sources), and some other metals.

Miniaturized green sample preparation approaches for pharmaceutical analysis

The development of green sample preparation procedures is an extremely important research field in which more and more applications are constantly being proposed in different areas, including pharmaceutical analysis. This review article is aimed at providing a general overview of the development of miniaturized green analytical sample preparation procedures in the pharmaceutical analysis field, with special focus on the works published between January 2017 and July 2021. Particular attention has been paid to the application of environmentally friendly solvents and sorbents as well as nanomaterials or high extraction capacity sorbents in which the solvent volumes and reagents amounts are drastically reduced, with their subsequent advantages from the sustainability point of view.

基于氧化石墨烯气凝胶固相萃取柱检测有机磷农药

以氧化石墨烯气凝胶三维纳米材料作为固相萃取的吸附剂,结合高效液相色谱,对食品中的有机磷农药(辛硫磷、双硫磷、倍硫磷、杀螟硫磷)进行检测分析。首先,利用冷冻干燥的方式制备得到氧化石墨烯气凝胶,通过扫描电镜、红外光谱、比表面积吸附等一系列的实验手段对其形貌及物理特性进行了表征,证明其成功合成。从扫描电镜中可见石墨烯的层状褶皱结构,其表面积为740.51 m²/g。然后,将氧化石墨烯气凝胶直接填充于固相萃取柱中,在未借助任何硅胶等基体的条件下进行萃取研究;通过单因素实验,系统研究了萃取和洗脱条件对有机磷农药萃取回收率的影响。结果显示,在上样体积15 mL、样品溶液pH值4、上样速率1.0 mL/min、洗脱剂1.0 mL乙腈的条件下萃取回收率最高。与商用的萃取材料进行比较,包括碳十八硅胶柱(C18)、阴离子交换柱(SAX)、氨基柱(-NH₂)和硅酸镁柱(Florisil),氧化石墨烯气凝胶填充的固相萃取柱的萃取回收率有明显提高。实验考察了氧化石墨烯气凝胶直接填充的萃取柱的寿命,结果显示该萃取柱可以重复使用15次,可见解决了分散无基体支撑的石墨烯纳米片容易破碎、堵塞筛板的问题。与液相色谱联用建立分析方法,4种有机磷农药的线性范围较宽,辛硫磷、双硫磷和倍硫磷的线性范围为1~200 μg/L,杀螟硫磷的线性范围为2~200 μg/L,线性拟合良好(线性相关系数r²≥0.9949),检出限为0.2~0.5 μg/L,满足于我国和其他国家限定标准的检测。将该方法应用于实际样品,在苹果皮中未检测到有机磷农药,对其进行加标,回收率为70.5%~93.6%,相对标准偏差≤10.4%。

Ionic-liquid-based ultrasound-assisted extraction combined with counter-current chromatography and semi-preparative-LC for the preparation of monoamine oxidase B inhibitors from Pueraria thomsonii

A simple and efficient method was developed for the rapid screening and identification of ligands for monoamine oxidase B. A new ionic-liquid-based ultrasound-assisted extraction method for medicinal herbs was also developed and validated. In addition, the hyphenated technique of counter-current chromatography and semi-preparative-LC was developed and applied to the isolation of the chemical constituents for Pueraria thomsonii Benth. Three potent monoamine oxidase B inhibitors, viz. daidzein-4',7-diglucoside (42.2 mg), puerarin 6''-O-xyloside (88.3 mg), and 3'-hydroxypuerarin (48.5 mg) with purities of 98.2%, 96.3%, and 97.1%, respectively, were obtained from 500 g of P. thomsonii raw material using semi-HPLC, whereas 3'-methoxypuerarin (76.2 mg), daidzein-8-C-apiosyl (1→6) glucoside (84.2 mg), and tectorigenin (75.1 mg) with purities of 98.5%, 96.4%, and 96.8%, respectively, were obtained from 500 g raw material via counter-current chromatography using a two-phase solvent system comprising n-hexane-ethyl acetate-methanol-water at a volume ratio of 1.85:1.00:0.86:3.69 (v/v). Then, the anti-Alzheimer activity of the phytochemicals was assessed using a PC12 cell model. Treatment with tectorigenin, daidzein-4',7-diglucoside, puerarin 6''-O-xyloside, 3'-hydroxypuerarin, 3'-methoxypuerarin, and daidzein-8-C-apiosyl (1→6) glucoside (100 μg/mL), resulted in cell viabilities of 69.00%, 65.81%, 59.69%, 57.90%, 55.61%, and 54.59%, respectively (P < 0.001). The protocol was proved to be very accurate and efficient. This article is protected by copyright. All rights reserved.

Development of a highly efficient in-tube solid-phase microextraction system coupled with UHPLC-MS/MS for analyzing trace hydroxyl polycyclic aromatic hydrocarbons in biological samples

Hydroxyl polycyclic aromatic hydrocarbons are considered active mutagenic and carcinogenic substances and are found in extremely low levels (ng/g) in biological samples. As a result, their determination in urine and blood samples is challenging, and a sensitive and effective method for the analysis of trace hydroxyl polycyclic aromatic hydrocarbons in complex biological matrices is required. In this work, a novel macroporous in-tube solid-phase microextraction monolith was prepared via a thiol-yne click reaction, and a highly efficient analytical method based on in-tube solid-phase microextraction coupled with UHPLC-MS/MS was developed to determine hydroxyl polycyclic aromatic hydrocarbons with low detection limits of 0.137-11.0 ng/L in complex biological samples. Four hydroxyl polycyclic aromatic hydrocarbons, namely, 2-hydroxyanthraquinone, 1-hydroxypyrene, 1,8-dihydroxyanthraquinone, and 6-hydroxychrysene, were determined in the urine samples of smokers, non-smokers, and whole blood samples of mice. Satisfactory recoveries were achieved in the range of 83.1-113% with relative standard deviations of 3.2-9.7%. It was found that implementation of the macroporous monolith gave a highly efficient approach for enriching trace hydroxyl polycyclic aromatic hydrocarbons in biological samples.

Fabrication of carbonyl-functional hypercrosslinked polymers as solid-phase extraction sorbent for enrichment of chlorophenols from water, honey and beverage samples

Three carbonyl-functional novel hypercrosslinked polymers (HCP-TPS, HCP-TPA, and HCP-TPP) were successfully fabricated through an one-step Friedel-Crafts acylation reaction by copolymerizing paraphthaloyl chloride with triphenylsilane, triphenylamine, and triphenylphosphine, respectively. The resultant HCPs contained plenty of carbonyl-functional groups. Among the series of such HCPs, HCP-TPS displayed the best adsorption capability to chlorophenols (CPs), and thus it was employed as solid-phase extraction (SPE) adsorbent for enrichment of chlorophenols from water, honey, and white peach beverage prior to determination by high-performance liquid chromatography. Under the optimal conditions, the detection limits of the method (S/N = 3) were 0.15-0.3 ng mL^-1 for tap water and leak water, 2.5-6.0 ng g^-1 for honey sample and 0.4-0.6 ng mL^-1 for white peach beverage sample. The recoveries of CPs in the spiked water, honey samples, and white peach beverage were in the range of 89.0-108.4%, 81.4-118.2%, and 85.0-113.5%, respectively. This work provides a new strategy for constructing functionalized HCPs as efficient SPE adsorbents. In this work, three novel hypercrosslinked polymers (HCPs) were synthesized by the Friedel-Crafts alkylation reaction (paraphthaloyl chloride as the alkylating agent, triphenylsilane, triphenylamine, and triphenylphosphine as the aromatic units). Then, HCP-TPS was applied to soild-phase extraction sorbent for enrichment CPs from water, honey, and white peach beverage samples.

Deep Eutectic Solvents Application in Food Analysis

Current trends in Analytical Chemistry are focused on the development of more sustainable and environmentally friendly procedures. However, and despite technological advances at the instrumental level having played a very important role in the greenness of the new methods, there is still work to be done regarding the sample preparation stage. In this sense, the implementation of new materials and solvents has been a great step towards the development of "greener" analytical methodologies. In particular, the application of deep eutectic solvents (DESs) has aroused great interest in recent years in this regard, as a consequence of their excellent physicochemical properties, general low toxicity, and high biodegradability if they are compared with classical organic solvents. Furthermore, the inclusion of DESs based on natural products (natural DESs, NADESs) has led to a notable increase in the popularity of this new generation of solvents in extraction techniques. This review article focuses on providing an overview of the applications and limitations of DESs in solvent-based extraction techniques for food analysis, paying especial attention to their hydrophobic or hydrophilic nature, which is one of the main factors affecting the extraction procedure, becoming even more important when such complex matrices are studied.

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.

Use of green alternative solvents in dispersive liquid-liquid microextraction: A review

Dispersive liquid-liquid microextraction is one of the most widely used microextraction techniques currently in the analytical chemistry field, mainly due to its simplicity and rapidity. The operational mode of this approach has been constantly changing since its introduction, adapting to new trends and applications. Most of these changes are related to the nature of the solvent employed for the microextraction. From the classical halogenated solvents (e.g., chloroform or dichloromethane), different alternatives have been proposed in order to obtain safer and non-pollutants microextraction applications. In this sense, low-density solvents, such as alkanols, switchable hydrophobicity solvents, and ionic liquids were the first and most popular replacements for halogenated solvents, which provided similar or better results than these classical dispersive liquid-liquid microextraction solvents. However, despite the good performances obtained with low-density solvents and ionic liquids, researchers have continued investigating in order to obtain even greener solvents for dispersive liquid-liquid microextraction. For that reason, in this review, the evolution over the last five years of the three types of solvents already mentioned and two of the most promising solvent alternatives (i.e., deep eutectic solvents and supramolecular solvents), have been studied in detail with the purpose of discussing which one provides the greenest alternative.

ZrO2 Nanoparticles and Poly(diallyldimethylammonium chloride)-Doped Graphene Oxide Aerogel-Coated Stainless-Steel Mesh for the Effective Adsorption of Organophosphorus Pesticides

A novel sorbent based on the ZrO₂ nanoparticles and poly(diallyldimethylammonium chloride)-modified graphene oxide aerogel-grafted stainless steel mesh (ZrO₂/PDDA-GOA-SSM) was used for the extraction and detection of organophosphorus pesticides (OPPs). Firstly, the PDDA and GO composite was grafted onto the surface of SSM and then freeze-dried to obtain the aerogel, which efficiently reduced the accumulation of graphene nanosheets. It integrated the advanced properties of GOA with a thin coating and the three-dimensional structural geometry of SSM. The modification of ZrO₂ nanoparticles brought a selective adsorption for OPPs due to the combination of the phosphate group as a Lewis base and ZrO₂ nanoparticles with the Lewis acid site. The ZrO₂/PDDA-GOA-SSM was packed into the solid-phase extraction (SPE) cartridge to extract OPPs. According to the investigation of different factors, the extraction recovery was mainly affected by the hydrophilic-hydrophobic properties of analytes. Effective extraction and elution parameters such as sample volume, sample pH, rate of sample loading, eluent, and eluent volume, were also investigated and discussed. Under the optimal conditions, the linearity of phoxim and fenitrothion was in the range of 1.0-200 μg L^-1, and the linearity of temephos was in the range of 2.5-200 μg L^-1. The limits of detection were ranged from 0.2 to 1.0 μg L^-1. This established method was successfully applied to detect OPPs in two vegetables. There was no OPP detected in real samples, and results showed that the matrix effects were in the range of 46.5%-90.1%. This indicates that the ZrO₂/PDDA-GOA-SSM-SPE-HPLC method could effectively extract and detect OPPs in vegetables.

Innovative extraction materials for fiber-in-tube solid phase microextraction: A review

Fiber-in-tube solid-phase microextraction (fiber-in-tube SPME) with short capillary longitudinally packed with fine fibers as extraction device allows direct coupling to high performance liquid chromatography (HPLC) systems to determine weakly volatile or thermally labile compounds. This technique associates the advantages of miniaturized and analytical on-line systems. Major achievements include the use of different capillaries (fused-silica, copper, stainless steel, polyetheretherketone (PEEK), or poly(tetrafluoroethylene) (PTFE)) that are packed with neat fibers (Zylon®, silk, or Kevlar 29®) or fibers (stainless steel, basalt, or carbon) functionalized with selective coatings (aerogels, ionic liquids (ILs), polymeric ionic liquids (PILs), molecularly imprinted polymers (MIPs), layered double hydroxides (LDHs), or conducting polymer). This review outlines the fundamental theory and the innovative extraction materials for fiber-in-tube SPME-HPLC systems and highlights their main applications in environmental and bioanalyses.

In-syringe temperature-controlled liquid-liquid microextraction based on solidified floating ionic liquid for the simultaneous determination of triazine and phenylurea pesticide in vegetable protein drinks

A novel in-syringe temperature-controlled liquid-liquid microextraction based on solidified floating ionic liquid (in-syringe TC-LLME-SFIL) combined with high performance liquid chromatography was developed for the simultaneous determination of monuron, chlorotoluron, atrazine, monolinuron, propazine and prometryn in commercial vegetable protein drinks. The samples were deproteinized by trichloroacetic acid and further cleaned up by solid phase extraction column. The ionic liquid tributyldodecylphosphonium tetrafluoroborate ([P_{4 4 4 12}]BF₄) was used as extraction solvent and dispersed into the depurated sample solution to form fine droplets with the assistance of heating and vortex. With the help of an ice bath, the ionic liquid phase solidified and floated on the surface of aqueous phase. After separation from the aqueous phase, the solidified ionic liquids were dissolved with acetonitrile and the resulting solution was analyzed by high performance liquid chromatography. Some extraction parameters, including type and amount of adsorbent, type and amount of ionic liquids, amount of NaCl, melting temperature and time of ionic liquid, vortex time, pH of sample solution, ice bath temperature and time, were investigated and optimized by single-factor experiment, Plackett-Burman design and Box-Behnken design. The results showed that good linearities (r ≥ 0.9994) were obtained in the concentration range of 7.8-1000.0 μg/L. The limits of detection and quantification were in the range of 0.25-2.59 μg/L and 0.82-8.63 μg/L, respectively. The spiked recoveries were 81.26-118.42% with the relative standard deviation (RSD, n = 3) lower than 8.17%. The present method was successfully applied to the simultaneous determination of triazine and phenylurea herbicides in vegetable protein drinks.

Recent advances in micro- and nanomaterial-based adsorbents for pipette-tip solid-phase extraction

There are a lot of review papers of sample pretreatment, but the comprehensive review on pipette-tip solid-phase extraction (PT-SPE) is lacking. This review (133 references) is mainly devoted to the development of different types of micro- and nanosorbent-based PT-SPE, including silica materials, carbon materials, organic polymers, molecularly imprinted polymers, and metal-organic frameworks. Each section mainly introduces and discusses the preparation methods, advantages and limitations of adsorbents, and their applications to environmental, biological, and food samples. This review also demonstrates the advantages of PT-SPE like convenience, speed, less organic solvent, and low cost. Finally, the future application and development trend of PT-SPE are prospected.

Recent Advances of Triazine-Based Materials for Adsorbent Based Extraction Techniques

This review mainly focused on the synthesis and properties of triazine-based materials as well as the state-of-the-art development of these materials in adsorption-based extraction techniques in the past 5 years, such as solid-phase extraction, magnetic solid-phase extraction, solid-phase microextraction and stir bar sorptive extraction, and the detection of various pollutants, including metal ions, drugs, estrogens, nitroaromatics, pesticides, phenols, polycyclic aromatic hydrocarbons and parabens. In the triazine-functionalized composites, triazine-based polymers and covalent triazine frameworks have been developed as the adsorbents with potential for environmental pollutants, mainly relying on the large surface area and the affinity of triazinyl groups with the targets. Triazine-based adsorbents have satisfactory sensitivity and selectivity towards different types of analytes, attributed from various mechanisms including π-π, electrostatics, hydrogen bonds, and hydrophobic and hydrophilic effects. The prospects of the materials for adsorption-based extraction were also presented, which can offer an outlook for the further development and applications.