Ionic liquids: solvents and sorbents in sample preparation

Ionic-liquid/Carbowax 20 M functionalized capsule phase microextraction platform for the extraction of phosphodiesterase-5 inhibitors from human serum and urine prior to their determination by LC-MS

Capsule phase microextraction (CPME) is an efficient bioanalytical technique that streamlines the sample preparation by integrating the filtration and stirring mechanism directly into the device. A novel composite sorbent designed to be selective towards the target analytes consisting of mixed-mode sorbent chemistry synthesized by sol-gel technology is found promising and superior to the conventional C18 sorbents. Herein we describe the encapsulation of an ionic liquid (IL)/Carbowax 20M-functionalized sol-gel sorbent (sol-gel IL/Carbowax 20 M) in the lumen of porous polypropylene tubes for the capsule phase microextraction of three phosphodiesterase-5 inhibitors namely avanafil, sildenafil, and tadalafil in human serum and urine samples. The CPME device was characterized by Scanning Electron Microscopy (SEM) and Fourier-Transform Infrared Spectroscopy (FT-IR). The experimental parameters of CPME procedure (e.g. sample pH and ionic strength, extraction time, stirring rate, elution solvent and volume) were carefully optimized to achieve the highest possible extraction efficiency for the analytes. Method validation was conducted in terms of precision, linearity, accuracy, matrix effect, lower limits of quantification, and limits of detection (LOD). The method linearity was investigated in the range of 50-1000 ng mL-1 for all analytes while the precision was less than 11.8 % in all cases. For all analytes, the LOD values were 17 ng mL-1. The IL/CW 20M-functionalized microextraction capsules could be reused at least 25 times both for urine and serum samples. The green character and the applicability of the proposed method were evaluated using the ComplexGAPI and BAGI indexes. The optimized CPME protocol exhibited reduced consumption of organic solvent and generation of waste, cost-effectiveness, and simplicity. Finally, the proposed method was successfully applied to the analysis of sildenafil in human urine after administration of drug-containing formulation.

Synthesis of imidazolium ionic liquid immobilized on magnetic mesoporous silica: A sorbent material in a green micro-solid phase extraction of multiclass pesticides in water

In this study, we synthesized an imidazolium ionic liquid immobilized on magnetic mesoporous silica (IL-MMS) and evaluated its performance as a sorbent material for a green micro-solid phase extraction (μ-SPE) of multiclass pesticides in water. The synthesized IL-MMS was characterized by various analytical techniques, including Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) analyses (N2 adsorption/desorption), Vibrating Sample Magnetometer (VSM), energy-dispersive spectroscopy (EDS) and Field emission scanning electron microscopy (FESEM). Our synthesized IL-MMS demonstrated excellent magnetic properties (31.5 emu/g), high surface area (1177.4 m2/g), proper pore size (⁓4.2 nm) and volume (1.80 cm3/g). Under optimized extraction conditions, the IL-MMS exhibited a high adsorption capacity for a variety of pesticides, including organophosphates, carbamates, and pyrethroids. The proposed μ-SPE method using IL-MMS showed good linearity (R2 > 0.99), low limits of detection (LODs) ranging from 0.04 to 1.63 ng/L, and suitable recovery rate was between 82.4% and 109.8% for different pesticides. In addition, the method also exhibited excellent reproducibility, with relative standard deviations (RSDs) of less than 8% for both intra and inter-day precision. In overall, the synthesized IL-MMS has proven to be a highly promising material for sorbent-based micro-solid phase extraction (μ-SPE) of multiclass pesticides in water. With its simple, efficient, and eco-friendly approach to pesticide analysis, this method shows great potential for future pesticide detection and monitoring efforts due to its sensitivity, accuracy, and adaptability to various environmental conditions.

Tailoring the Properties of Gel Polymer Electrolytes for Sodium-Ion Batteries Using Ionic Liquids: A Review

Ionic liquids are an extraordinary group of compounds, fully ionic in structure like inorganic salts but with low melting points, that resemble organic molecular solvents. Their chemical, electrochemical, and thermal stability is what draws the attention and enables their use in many applications, including electrochemical power sources. Even though they are no longer considered eco-friendly because of nonnegligible toxicity and long bioaccumulation, they can still be efficiently recovered, purified, and reused. These attributes can be harvested to enhance the properties of gel polymer electrolytes for the emerging sodium-ion batteries. The variety of anions and cations for ILs and their influence on the final properties of the compound opens the road to tuning the properties of gel polymer electrolytes. Ionic liquids as plasticizers constitute a major part of gel polymer electrolytes (average of 70 wt%) and hence, they affect the fundamental properties of gel electrolytes like ionic conductivity and electrochemical window. They also improve the safety features of sodium-ion batteries, which is relevant for their anticipated applications in stationary energy storage and electric vehicles. The presented review paper aims to explain the relationship between the cation and anion in ionic liquid and the properties of gel electrolytes for sodium-ion batteries.

Concentrated ionic liquids for proteomics: Caveat emptor!

The use of concentrated ionic liquids (ILs) in the bioanalytical chemistry of proteins is sparse; typically, dilute aqueous IL solutions are used. Concentrated ILs have unique properties that may allow researchers to dissolve previously insoluble protein analytes, to increase the depth and robustness of sample preparation and the analysis of proteins. Previous research using concentrated ILs for this purpose is sparse and there is a need to systematically investigate the structure-activity relationship between the IL structure and its capacity to solubilise proteins. Here, bovine serum albumin was dissolved in various ionic liquids and monitored over time by light microscopy and SDS-PAGE. While qualitative, these measures provide a good estimate of, respectively, the dissolving power of an IL towards the given protein and the retained integrity of the protein. Hydrophilic ILs show the best solubilisation capacity and higher temperatures (in a restricted sense) improve the solubility of the protein. Higher temperatures and longer reaction times reduce the molecular weight of the protein, which could inhibit their applicability in proteomics, unless the conditions are judiciously controlled. Researchers should exercise caution when using concentrated ILs for protein analysis until the full scope and limitations are known, an aspect we are presently investigating.

Fabricating a designer capsule phase microextraction platform based on sol-gel Carbowax 20M-zwitterionic ionic liquid composite sorbent for the extraction of lipid-lowering drugs from human urine samples

A sol-gel Carbowax 20 M/3-[(3-Cholamidopropyl) dimethyl ammonio]-1-propanesulfonate composite sorbent-based capsule phase microextraction device has been fabricated and characterized for the determination of four statins (pravastatin, rosuvastatin, pitavastatin, and atorvastatin) in human urine. The presence of ionizable carboxyl functional groups in statins requires pH adjustment of the sample matrix to ensure that the target molecules are in their protonated form (pH should be 2 units below their pKa values) which not only is cumbersome but also risks unintended contamination of the sample. This challenge was addressed by introducing zwitterionic ionic liquid in addition to neutral, polar Carbowax 20 M polymer in the sol-gel-derived composite sorbent. As such, the composite zwitterionic multi-modal sorbent can simultaneously extract neutral, cationic, and anionic species. This particular attribute of the composite sorbent eliminates the necessity of the matrix pH adjustment and consequently simplifies the overall sample preparation workflow. Various experimental parameters such as the sample amount, extraction time, salt addition, stirring rate, and elution solvent type that may affect the extraction performance of the statins were investigated using a central composite design and the one-parameter-at-a-time approach. The analytes and the internal standard were separated on a C18 column with gradient elution using phosphate buffer (20 mM, pH 3) and acetonitrile as mobile phase. The analytes were detected at 237 nm. The method was validated, and linearity was observed in the range 0.10-2.0 μg mL-1 for all compounds. The method precision was better 9.9% and 10.4% for intra-day and inter-day, respectively, while the relative recoveries were acceptable, ranging between 83.4 and 116% in all cases. Method greenness was assessed using the ComplexGAPI index. Finally, the method's applicability was demonstrated in the determination of the statins in authentic human urine after oral administration of pitavastatin and rosuvastatin-containing tablets.

Effects of ionic liquids on biomembranes: A review on recent biophysical studies

Ionic liquids (ILs) have been emerged as a versatile class of compounds that can be easily tuned to achieve desirable properties for various applications. The ability of ILs to interact with biomembranes has attracted significant interest, as they have been shown to modulate membrane properties in ways that may have implications for various biological processes. This review provides an overview of recent studies that have investigated the interaction between ILs and biomembranes. We discuss the effects of ILs on the physical and chemical properties of biomembranes, including changes in membrane fluidity, permeability, and stability. We also explore the mechanisms underlying the interaction of ILs with biomembranes, such as electrostatic interactions, hydrogen bonding, and van der Waals forces. Additionally, we discuss the future prospects of this field.

Batch Scale Production of 3D Printed Extraction Sorbents Using a Low-Cost Modification to a Desktop Printer

This study reports a simple modification to a commercial resin 3D printer that significantly reduces the amount of prepolymer material needed for the production of extraction sorbents. The modified printing platform is demonstrated in the printing of two imidazolium-based ionic liquid (IL) monomers. Two geometries resembling a blade-type polymeric ionic liquid (PIL) sorbent used in thin-film microextraction and a fiber-type sorbent used in solid-phase microextraction (SPME) were printed. The SPME PIL sorbents were used to extract 10 organic contaminants, including plasticizers, antimicrobial agents, UV filters, and pesticides, from water followed by high-performance liquid chromatographic (HPLC) analysis. To compare the extraction performance of the SPME sorbents, seven fibers printed with the same prepolymer composition from the same printing batch as well as different batches were evaluated. The results revealed highly reproducible extraction efficiencies for all tested sorbents with no statistical difference in their extraction performance. Method validation showed acceptable linearity (R2 > 0.92) for all analytes with limits of detection and limits of quantification ranging from 0.13 to 45 μg L-1 and 0.43 to 150 μg L-1, respectively.

Chronic and intergenerational toxic effects of 1-decyl-3-methylimidazolium hexafluorophosphate on the water flea, Moina macrocopa

With the increasing use and production of "green solvents" ionic liquids (ILs) and their known stability in the environment, the potential adverse effects of ILs have become a focus of research. In the present study, acute, chronic, and intergenerational toxic effects of an imidazolium-based ionic liquid, 1-decyl-3-methylimidazolium hexafluorophosphate ([Demim]PF6), on Moina macrocopa were investigated following the parental exposure. The results showed that [Demim]PF6 exhibited high toxicity to M. macrocopa, and the long-term exposure significantly inhibited the survivorship, development, and reproduction of the water flea. Furthermore, it is also observed that [Demim]PF6 induced toxic effects in the following generation of M. macrocopa, resulting in the complete cessation of reproduction in the first offspring generation, and the growth of the organisms was also significantly affected. These findings provided a novel insight into the intergenerational toxicity induced by ILs to crustaceans and suggested that these compounds pose potential risks to the aquatic ecosystem.

MOFs Containing Solid-State Electrolytes for Batteries

The use of metal-organic frameworks (MOFs) in solid-state electrolytes (SSEs) has been a very attractive research area that has received widespread attention in the modern world. SSEs can be divided into different types, some of which can be combined with MOFs to improve the electrochemical performance of the batteries by taking advantage of the high surface area and high porosity of MOFs. However, it also faces many serious problems and challenges. In this review, different types of SSEs are classified and the changes in these electrolytes after the addition of MOFs are described. Afterward, these SSEs with MOFs attached are introduced for different types of battery applications and the effects of these SSEs combined with MOFs on the electrochemical performance of the cells are described. Finally, some challenges faced by MOFs materials in batteries applications are presented, then some solutions to the problems and development expectations of MOFs are given.

Preparation of Cellulose Nanocrystals by Synergistic Action of Ionic Liquid and Recyclable Solid Acid under Mild Conditions

Cellulose nanocrystals (CNCs) are nanoscale particles made from cellulose. They have many unique properties such as being lightweight, stiff, and renewable, making them promising for a variety of applications in a wide range of industries, including materials science, energy storage, and biomedicine. In this paper, a two-stage (swelling-SA-catalyzed) method including IL pretreatment and solid acid hydrolysis process was developed to extract CNCs with high purity and good thermal stability from microcrystalline cellulose (MCC). In the first stage, the swelling of MCC in ionic liquid was studied with the assistance of ultrasonication, and it was found that the amorphous regions became more disordered while the crystalline areas were selectively retained under the conditions of 30 min of reaction time, 45 °C of temperature, 2% of ionic liquid water content and 1:4 mass ratio of cellulose to ionic liquid. CNCs were extracted using solid acid hydrolysis, with a 45 wt% solid acid to cellulose ratio and a 5.0 h hydrolysis process at 45 °C. The morphology, crystallinity, surface characteristics and thermo stability of the sample were characterized by atomic force microscopy (AFM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA), respectively. Results demonstrated the highly thermostable CNCs were successful extracted with rodlike shape of 300 ± 100 nm in length and 20 ± 10 nm in width. Solid acid recovery and reuse were also studied, revealing a promising candidate that can reduce the environmental impact associated with chemical products.

Shear-induced phase transition in the aqueous solution of an imidazolium-based ionic liquid

An ionic liquid (IL) is a salt in the liquid state that consists of a cation and an anion, one of which possesses an organic component. Because of their non-volatile property, these solvents have a high recovery rate, and, hence, they are considered as environment-friendly green solvents. It is necessary to study the detailed physicochemical properties of these liquids for designing and processing techniques and find suitable operating conditions for IL-based systems. In the present work, the flow behavior of aqueous solutions of an imidazolium-based IL, 1-methyl-3-octylimidazolium chloride, is investigated, where the dynamic viscosity measurements indicate non-Newtonian shear thickening behavior in the solutions. Polarizing optical microscopy shows that the pristine samples are isotropic and transform into anisotropic after shear. These shear thickened liquid crystalline samples change into an isotropic phase upon heating, which is quantified by the differential scanning calorimetry. The small angle x-ray scattering study revealed that the pristine isotropic cubic phase of spherical micelles distort into non-spherical micelles. This has provided the detailed structural evolution of mesoscopic aggregates of the IL in an aqueous solution and the corresponding viscoelastic property of the solution.

Applications of magnetic and electromagnetic forces in micro-analytical systems

Novel applications of magnetic fields in analytical chemistry have become a remarkable trend in the last two decades. Various magnetic forces have been employed for the migration, orientation, manipulation, and trapping of microparticles, and new analytical platforms for separating and detecting molecules have been proposed. Magnetic materials such as functional magnetic nanoparticles, magnetic nanocomposites, and specially designed magnetic solids and liquids have also been developed for analytical purposes. Numerous attractive applications of magnetic and electromagnetic forces on magnetic and non-magnetic materials have been studied, but fundamental studies to understand the working principles of magnetic forces have been challenging. These studies will form a new field of magneto-analytical science, which should be developed as an interdisciplinary field. In this review, essential pioneering works and recent attractive developments are presented.

Role and Recent Advancements of Ionic Liquids in Drug Delivery Systems

Advancements in the fields of ionic liquids (ILs) broaden its applications not only in traditional use but also in different pharmaceutical and biomedical fields. Ionic liquids "Solutions for Your Success" have received a lot of interest from scientists due to a myriad of applications in the pharmaceutical industry for drug delivery systems as well as targeting different diseases. Solubility is a critical physicochemical property that determines the drug's fate at the target site. Many promising drug candidates fail in various phases of drug research due to poor solubility. In this context, ionic liquids are regarded as effective drug delivery systems for poorly soluble medicines. ILs are also able to combine different anions/cations with other cations/anions to produce salts that satisfy the concept behind the ILs. The important characteristics of ionic liquids are the modularity of their physicochemical properties depending on the application. The review highlights the recent advancement and further applications of ionic liquids to deliver drugs in the pharmaceutical and biomedical fields.

Thermoresponsive Ionic Liquid with Different Cation-Anion Pairs as Draw Solutes in Forward Osmosis

We synthesized various phosphonium- and ammonium-based ionic liquids (ILs), using benzenesulfonate (BS) and 4-methylbenzenesulfonate (MBS) to establish the criteria for designing an ideal draw solute in a forward osmosis (FO) system. Additionally, the effects of monocationic, dicationic, and anionic species on FO performance were studied. Monocationic compounds ([P₄₄₄₄][BS], [P₄₄₄₄][MBS], [N₄₄₄₄][BS], and [N₄₄₄₄][MBS]) were obtained in one step via anion exchange. Dicationic compounds ([(P₄₄₄₄)₂][BS], [(P₄₄₄₄)₂][MBS], [(N₄₄₄₄)₂][BS], and [(N₄₄₄₄)₂][MBS]) were prepared in two steps via a Menshutkin SN₂ reaction and anion exchange. We also investigated the suitability of ILs as draw solutes for FO systems. The aqueous [P₄₄₄₄][BS], [N₄₄₄₄][BS], [N₄₄₄₄][MBS], and [(N₄₄₄₄)₂][BS] solutions did not exhibit thermoresponsive behavior. However, 20 wt% [P₄₄₄₄][MBS], [(P₄₄₄₄)₂][BS], [(P₄₄₄₄)₂][MBS], and [(N₄₄₄₄)₂][MBS] had critical temperatures of approximately 43, 33, 22, and 60 °C, respectively, enabling their recovery using temperature. An increase in IL hydrophobicity and bulkiness reduces its miscibility with water, demonstrating that it can be used to tune its thermoresponsive properties. Moreover, the FO performance of 20 wt% aqueous [(P₄₄₄₄)₂][MBS] solution was tested for water flux and found to be approximately 10.58 LMH with the active layer facing the draw solution mode and 9.40 LMH with the active layer facing the feed solution.

A Human Oral Fluid Assay for D- and L- Isomer Detection of Amphetamine and Methamphetamine Using Liquid-Liquid Extraction

Medical providers are increasingly confronted with clinical decision-making that involves (meth)amphetamines. And clinical laboratories need a sensitive, efficient assay for routine assessment of D- and L-isomers to determine the probable source of these potentially illicit analytes. This paper presents a validated method of D- and L-isomer detection in human oral fluid from an extract used for determination of a large oral fluid assay (63 analytes) on an older AB SCIEX 4000 instrument. Taken from the positive extract, D- and L-analytes were added. The method for extraction included addition of internal standard and a 2-step liquid-liquid extraction and dry-down step to concentrate and clean the samples. The samples were suspended in 50% MeOH in water, diluted with mobile phase, with separation and detection accomplished using LC-MS/MS to determine analyte concentration. Once samples were confirmed positive for (meth)amphetamine from the large oral fluid assay, they were further examined for the enantiomeric forms with 50 μl aliquots of the standards and samples of interest combined with 450 μl of D- and L-assay mobile phase, then analyzed using chiral column separation, and LC-MS/MS detection with standard curve spanning the range from 2.5 to 1000 ng/mL. The result is a sensitive and accurate detection of D- and L-isomers of amphetamine and methamphetamine in human oral fluid performed on an older model mass spectrometer (AB SCIEX 4000). The novelty of this assay is twofold (a) the 2-step liquid-liquid extraction and dry-down step to concentrate and clean the samples, and (b) its adoption characteristics as a reflex test from a large ODT panel without the need to invest in newer or expensive LC-MS/MS instruments. Finally, this assay also has potential to add a valuable option to high-throughput laboratories seeking a D- and L-testing alternative to urine drug testing methods.

Self-Assembly of a C16M[Mn] Magnetic Surfactant in Water

A magnetic surfactant, which combines the properties of a surfactant with magnetic responsiveness, shows great potential in biotechnology, separation, adsorption, and catalysis, especially in non-invasive manipulation through a magnetic field. However, a molecularly magnetic surfactant is usually paramagnetic for the amorphous and less ordered structures. In this work, magnetic surfactant 1-methyl-3-hexadecane-imidazolium [MnCl₂Br] (C₁₆M[Mn]) is reported to self-assemble in water. The C₁₆M[Mn] magnetic surfactant self-assembles in water to form a lamellar hydrogel from 10 to 50 wt % at and below room temperature. The hydrogel changes from a gel to a sol at 30 °C, and the hexadecane chains in the hydrogel change from noncrystalline to crystalline at 0 °C. In the hydrogel state, the lamellar domain spacing is varied from 36 to 45 nm depending on the concentration and self-assembly temperature. After self-assembly, the magnetic susceptibility of the freeze-dried magnetic surfactant is increased. Most important is the fact that the freeze-dried sample at a high concentration (40-50 wt %) shows the highest magnetic susceptibility, which is related to the closer molecular packing and the more ordered structures. The self-assembly-induced increase in magnetic susceptibility provides a method for improving the magnetic properties of a magnetic surfactant.

Exploring ionic liquid-laden metal-organic framework composite materials as hybrid electrolytes in metal (ion) batteries

This review focuses on the combination of metal-organic frameworks (MOFs) and ionic liquids (ILs) to obtain composite materials to be used as solid electrolytes in metal-ion battery applications. Benefiting from the controllable chemical composition, tunable pore structure and surface functionality, MOFs offer great opportunities for synthesizing high-performance electrolytes. Moreover, the encapsulation of ILs into porous materials can provide environmentally benign solid-state electrolytes for electrochemical devices. Due to the versatility of MOF-based materials, in this review we also explore their use as anodes and cathodes in Li- and Na-ion batteries. Finally, solid IL@MOF electrolytes and their implementation into Li and Na batteries have been analyzed, as well as the design and advanced manufacturing of solid IL@MOF electrolytes embedded on polymeric matrices.

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.

Kinetics and mechanism of Eu(III) transfer in tributyl phosphate microdroplet/HNO3 aqueous solution system revealed by fluorescence microspectroscopy

In this study, we reveal an Eu(III) extraction mechanism at the interface between HNO₃ and tributyl phosphate (TBP) solutions using fluorescence microspectroscopy. The mass transfer rate constant at the interface is obtained from the analysis of fluorescence intensity changes during the forward and backward extractions at various HNO₃ and TBP concentrations to investigate the reaction mechanism. This result indicates that one nitrate ion reacts with Eu(III) at the interface, whereas TBP molecules are not involved in the interfacial reaction, which is different from the results obtained using the NaNO₃ solution in our previous study. We demonstrate that the chemical species of Eu(III) complex with nitrate ion and TBP in the aqueous solution play an important role for the extraction mechanism. The rate constants of the interfacial reactions in the forward and backward extractions are (4.0-5.0) × 10^-7 m M^-1 s^-1 and (3.2-3.3) × 10^-6 m s^-1, respectively. We expect that our revealed mechanism provides useful and fundamental knowledge for actual solvent extraction.

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.

Atom surface fragment contribution method for predicting the toxicity of ionic liquids

In this study, a novel method-atom surface fragment contribution (ASFC)-was proposed for assessing the properties of compounds. We developed a predictive model using the ASFC method based on the sigma surface areas (S_σ-surface) of fragments/groups for estimating the toxicity of ILs. A toxicity dataset of 140 ILs towards leukemia rat cell line (ICP-81) was gathered and employed to train and validate models. The S_σ-surface values of atoms in each group were firstly calculated from the COSMO profiles of cations and anions for ILs. Then the S_σ-surface values of 26 groups were obtained and used as input descriptors for modelling. The R² and MSE of the built ASFC model were 0.924 and 0.071, respectively. Results indicate that the ASFC model developed by the new approach possesses great accuracy and reliability. In total, the ASFC method has extensive potential for the application of estimating diverse properties of ILs and other compounds due to its remarkable advantages.

A novel route for identifying starch diagenetic products in the archaeological record

This work introduces a novel analytical chemistry method potentially applicable to the study of archaeological starch residues. The investigation involved the laboratory synthesis of model Maillard reaction mixtures and their analysis through Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS). Thus, starch from sixteen plant species were matured while reacting it with the amino acid glycine. The FTICR-MS analysis revealed > 5,300 molecular compounds, with numerous unique heteroatom rich compound classes, ranging from 20 (Zea mays) to 50 (Sorghum bicolor). These classes were investigated as repositories of chemical structure retaining source and process-specific character, linked back to botanical provenance. We discussed the Maillard reaction products thus generated, a possible pathway for the preservation of degraded starch, while also assessing diagenetic recalcitrance and adsorption potential to mineral surfaces. In some cases, hydrothermal experimentation on starches without glycine reveals that the chemical complexity of the starch itself is sufficient to produce some Maillard reaction products. The article concludes that FTICR-MS offers a new analytical window to characterize starchy residue and its diagenetic products, and is able to recognize taxonomic signals with the potential to persist in fossil contexts.

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.

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.

Microextraction by packed sorbent of selected pesticides in coffee samples employing ionic liquids supported on graphene nanosheets as extraction phase

This paper describes the synthesis, characterization, and use of ionic liquids supported on silica, functionalized with graphene oxide through covalent bonding (ILz/Si@GO), as sorbents for microextraction by packed sorbent (MEPS). Seven selected pesticides (diazinon, heptachlor, aldrin, endrin, dieldrin, endosulfan, and methoxychlor), used for the prevention of pests in coffee crops, and endosulfan sulfate-an endosulfan metabolite-were selected for this study as model compounds for evaluating the sorbent performance of the synthesized materials in the MEPS device. The cycles of each of the stages were previously optimized through univariate experiments to carry out the extraction. The ILz/Si@GO phase was compared to other sorbents used in MEPS (GO, DVB-MMA, C₄/SiO₂, C₈/SiO₂, ILz/SiO₂, and bare silica) and also with graphene functionalized through other methodologies, where ILz/Si@GO showed the best results. The material was characterized using a range of techniques. The selectivity of the sorbent material and its adsorption capacity were evaluated by gas chromatography coupled with tandem mass spectrometry. The precision and accuracy of the method showed a relative standard deviation lower than 10% and recoveries from 35 to 97%. Finally, the proposed method was employed for the determination of pesticide residues in coffee samples.

Thermodynamics and structure of model bio-membrane of liver lipids in presence of imidazolium-based ionic liquids

Ionic liquids (ILs) are the attractions of researchers today due to their vast area of potential applications. For biomedical uses, it becomes essential to understand their interactions with cellular membrane. Here, the membrane is mimicked with lipid bilayer and monolayer composed of liver lipids extract. Three archetypal imidazolium based ILs, 1-decyl-3-methylimidazolium tetrafluoroborate ([DMIM][BF4] or [C10MIM][BF4]), 1-octyl-3-methylimidazolium tetrafluoroborate, ([OMIM][BF4] or [C8MIM][BF4]) and 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4] or [C2MIM][BF4]) having different alkyl chain lengths are used in the present study. The isothermal titration calorimetry (ITC) measurements showed that [DMIM][BF4] interacts strongest with the liver lipid membrane compared to other two ILs which have relatively shorter alkyl chain length. The low values of stoichiometry ratio of ILs indicates that ILs penetrate within the core of the lipid bilayer. The interaction of ILs with the liver lipid membrane is found to be mainly driven by entropy which could be due to the change in the structure of the lipid membrane at local or global scales. Dynamic light scattering (DLS) measurements indicate that there are no changes in the size of vesicles due to addition of [DMIM][BF4] indicating stability of the vesicles. On the other hand, x-ray reflectivity (XRR) measurements showed a concentration dependent change in the monolayer structure. At low concentration of the IL, the monolayer thickness decreases, exhibiting an increase in the electron density of the layer. However, at higher concentrations, the monolayer thickness increases proving a concentration dependent effects of the IL on the arrangement of the molecules.

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%.

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.

Determination of bisphenol A: Old problem, recent creative solutions based on novel materials

Bisphenol A is a synthetic compound widely used in industry, in the production of polycarbonate, epoxy resins, and thermal paper, among others. Its annual production is estimated at millions of tons per year, demonstrating its importance. Despite its wide application in various everyday products, once in the environment (due to its disposal or leaching), it has high toxicity to humans and animal life, and this problem has been well known for years. Given this problem, many researchers seek alternatives for its monitoring in matrices such as natural water, waste, food, and biological matrices. For this, new advanced materials have been developed, characterized, and applied in creative ways for the preparation of samples for the determination of bisphenol A. This article aims to present some of these important and recent applications, describing the use of molecularly imprinted polymers, metal and covalent organic frameworks, ionic liquids and magnetic ionic liquids, and deep eutectic solvents as creative solutions in sample preparation for the long-standing problem of bisphenol A determination.

Poly(ionic liquid)s as new adsorbents in dispersive micro-solid-phase extraction of unmodified and modified oligonucleotides

Cross-linked poly(ionic liquid)s were successfully used for the first time in the preparation of oligonucleotide biological samples. The adsorbents were prepared by co-polymerization of imidazolium-based ionic liquids and divinylbenzene. Consequently, the following three adsorbents were prepared and comprehenzively characterized: poly(3-butyl-1-vinylimidazolium bromide-co-divinylbenzene), poly(3-hexyl-1-vinylimidazolium bromide-co-divinylbenzene) and poly(2-(1-vinylimidazoliumyl)acetate-co-divinylbenzene). Oligonucleotides were adsorbed onto the surface of these materials at low pH values. Preliminary studies of the desorption of the analytes included testing the influence of different types of salts, as well as their concentrations and pH, and organic solvents on the recovery. This allowed for determining the adsorbent and the desorption conditions for further optimization with the use of central composition design. The chosen adsorbent was poly(2-(1-vinylimidazoliumyl)acetate-co-divinylbenzene), and the optimal desorption conditions (5 mM ammonium acetate (pH = 9.5)/methanol (50/50, v/v)) gave a recovery of 99.7 ± 0.3%. The dispersive micro-solid-phase extraction procedure was successfully applied for the extraction of oligonucleotides with various modifications and lengths. Finally, the developed method was used to extract 2'-O-methyl oligonucleotide and its two synthetic metabolites from enriched human plasma without any pre-purification, yielding recoveries over 80%.

Relating the physical properties of aqueous solutions of ionic liquids with their chemical structures

The physical properties of an aqueous solution of a macromolecule primarily depend on its chemical structure and the mesoscopic aggregates formed by many of such molecules. Ionic liquids (ILs) are the macromolecules that have caught significant research interests for their enormous industrial and biomedical applications. In the present paper, the physical properties, such as density, viscosity, ionic conductivity of aqueous solutions of various ILs, have been investigated. These properties are found to systematically depend on the shape and size of the anion and the cation along with the solution concentration. The ionic conductivity and viscosity behavior of the solutions do not strictly follow the Walden rule that relates the conductivity to the viscosity of the solution. However, the modified Walden rule could explain the behavior. A simple calculation based on the geometry of a given molecule could shed the light on the observed results.

Novel materials for dispersive (micro) solid-phase extraction of polycyclic aromatic hydrocarbons in environmental water samples: A review

Polycyclic aromatic hydrocarbons are hazardous environmental pollutants that possess mutagenic and carcinogenic properties. Generally, the concentrations of PAHs in environmental water samples are very low, and it is challenging to detect such levels directly by the analytical instrumentation. Thus, the extraction of PAHs using suitable extraction methodology is required for sample cleanup and analyte enrichment. Dispersive solid-phase extraction has several advantages over conventional approaches for the extraction of PAHs from environmental water samples. In this article, we critically evaluate the role of different nano and micro sorbent materials employed in the extraction of PAHs. Carbon-based nanomaterials, metal-organic frameworks, polymeric nanocomposites, ionic-liquid based composites, and silica-based materials are explicitly covered. This review also provides insight on functional components of all types of sorbents and their way of interaction with PAHs. The factors affecting the dispersive (micro) solid phase extraction of PAHs such as the design of the sorbent, the ratio of functional material to magnetic core, sample volume, amount of sorbent, extraction and desorption times, desorption solvent and its volume, salt addition, and sample pH are critically appraised. Finally, a brief account on the accomplishments, limitations, and challenges associated with such methods is provided.

Removal of nickel from aqueous solution using synthesized IL/ZnO NPs

In this paper, the removal of nickel from aqueous solution was studied using zinc oxide nanoparticles (ZnO NPs) and zinc oxide nanoparticles functionalized ionic liquid (IL/ZnO NPs) by batch adsorption and solid phase extraction (SPE) methods, respectively. The synthesized IL/ZnO NPs was characterized by FT-IR, SEM, XRD, XPS, and DLS techniques. The optimum conditions were experimentally determined by varying the parameters such as feed concentration, contact time, adsorbent dosage, pH, and temperature using both the adsorbents. From the optimum conditions, it was found that the feed concentration is 10 ppm, contact time is 120 min, adsorbent dosage is 0.2 g, pH is 6, and temperature is 60 °C with the maximum percentage removal of 81% for ZnO Nps, whereas, for IL/ZnO NPs, the feed concentration is 10 ppm, contact time is 90 min, adsorbent dosage is 0.1 g, pH is 6, and temperature is 60 °C with the maximum percentage removal of 92.5%. On comparison with the results, IL/ZnO NPs was an efficient adsorbent for the removal of nickel from aqueous solution as well as the effluents of electroplating and stainless steel industries. The percentage removal of nickel was analyzed by inductively coupled plasma-optical emission spectrometry (ICP-OES). The sorbents were regenerated and reused effectively.