Deep eutectic solvents as green and sustainable diluents in headspace gas chromatography for the determination of trace level genotoxic impurities in pharmaceuticals.

Genotoxic impurities (GTIs) are potential carcinogens that need to be controlled down to ppm or lower concentration levels in pharmaceuticals under strict regulations. The static headspace gas chromatography (HS-GC) coupled with electron capture detection (ECD) is an effective approach to monitor halogenated and nitroaromatic genotoxins. Deep eutectic solvents (DESs) possess tunable physico-chemical properties and low vapor pressure for HS-GC methods. In this study, zwitterionic and non-ionic DESs have been used for the first time to develop and validate a sensitive analytical method for the analysis of 24 genotoxins at sub-ppm concentrations. Compared to non-ionic diluents, zwitterionic DESs produced exceptional analytical performance and the betaine : 7 (1,4- butane diol) DES outperformed the betaine : 5 (1,4-butane diol) DES. Limits of detection (LOD) down to the 5-ppb concentration level were achieved in DESs. Wide linear ranges spanning over 5 orders of magnitude (0.005-100 µg g-1) were obtained for most analytes with exceptional sensitivities and high precision. The method accuracy and precision were validated using 3 commercially available drug substances and excellent recoveries were obtained. This study broadens the applicability of HS-GC in the determination of less volatile GTIs by establishing DESs as viable diluent substitutes for organic solvents in routine pharmaceutical analysis.

Exploring a new generation of bimetallic magnetic ionic liquids with ultra-low viscosity in microextraction that enable direct coupling with high-performance liquid-chromatography.

BACKGROUND: The incorporation of bimetallic magnetic ionic liquids (MILs) in microextraction methods is an emerging trend due to the improved magnetic susceptibility offered by these solvents, which relies on the presence of metallic components in both the cation and the anion. This feature favors easy magnetic separation of these solvents in analytical sample preparation strategies. However, reported liquid-phase microextraction methods based on bimetallic MILs still present an important drawback in that the MILs are highly viscous, making a dispersive solvent during the microextraction procedure necessary, while also requiring a tedious back-extraction step prior to the chromatographic analysis. RESULTS: We propose for the first time a new generation of ultra-low viscosity bimetallic MILs composed of two paramagnetic Mn(II) complexes characterized by their easy usage in dispersive liquid-liquid microextraction (DLLME). The approach does not require dispersive solvent and the MIL-DLLME setup was directly combined with high-performance liquid chromatography (HPLC) and fluorescence detection (FD), without any back-extraction step. The approach was evaluated for the determination of five monohydroxylated polycyclic aromatic hydrocarbons, as carcinogenic biomarkers, in human urine. Optimum conditions of the MIL-DLLME method included the use of a low MIL volume (75 µL), a short extraction time (5 min), and no need of any dispersive solvent neither NaCl. The method presented limits of detection down to 7.50 ng L-1, enrichment factors higher than 17, and provided inter-day relative standard deviation lower than 11%. Analysis of urine samples was successfully performed, with biomarker content found at levels between 0.24 and 7.8 ng mL-1. SIGNIFICANCE: This study represents the first liquid-phase microextraction method using the new generation of low-viscous bimetallic MILs. The proposed MIL-DLLME approach represents 2 important advances with respect to previous methods employing bimetallic MILs: 1) no dispersive solvent is required, and 2) direct injection of the MIL in the HPLC is possible after minor dilution (no back extraction steps are required). Therefore, the microextraction strategy is simple, rapid, and consumes very small amounts of energy.

Multivariate optimization for extraction of 2-methylimidazole and 4-methylimidazole from açaí-based food products using polymeric ionic liquid-based sorbent coatings in solid-phase microextraction coupled to gas chromatography-mass spectrometry.

In this study, polymeric ionic liquids featuring different functional moieties were applied as sorbent coatings in direct-immersion solid-phase microextraction (DI-SPME) for the extraction of 2-methylimidazole (2-MI) and 4-methylimidazole (4-MI) from açaí-based food products followed by gas chromatography-mass spectrometry (GC-MS) analysis. The analytical method was optimized using a sequential experimental design. Variables used in GC-MS such as desorption time, as well as for SPME-DI, including extraction time, extraction temperature, incubation time of extraction, amount of NaCl in the extract, and stirring rate, were optimized. The fitness-for-purpose of the method was verified by the linearity of matrix-matched calibration curves (R2 ≥ 0.9921), adequate recoveries (81.7-89.7 %), and precision (relative standard deviations ≤11.2 %). The method was applied to twenty-five samples of açaí-based food products. 4-MI was found in four samples whereas 2-MI was not detected above the limit of detection. The method was found to be suitable for quality control analysis.

Extraction of volatile organic compounds liberated upon filament extrusion by 3D pen and its comparison with a desktop 3D printer using solid-phase microextraction fiber and Arrow.

Desktop 3D printers that operate by the fused deposition modeling (FDM) mechanism are known to release numerous hazardous volatile organic compounds (VOCs) during printing, including some with potential carcinogenic effects. Operating in a similar manner to FDM 3D printers, 3D pens have gained popularity recently from their ability to allow users to effortlessly draw in the air or create various 3D printed shapes while handling the device like a pen. In contrast to numerous modern 3D printers, 3D pens lack their own ventilation systems and are often used in settings with minimum airflow. Their operation makes users more vulnerable to VOC emissions, as the released VOCs are likely to be in the breathing zone. Consequently, monitoring VOCs released during the use of 3D pens is crucial. In this study, VOCs liberated while extruding acrylonitrile butadiene styrene (ABS) filaments from a 3D pen were measured by solid-phase microextraction (SPME) combined with gas chromatography/mass spectrometry (GC/MS). SPME was investigated using the traditional fiber and Arrow geometries with the DVB/Carbon WR/PDMS sorbent while four different brands of ABS filaments-Amazon Basics, Gizmodork, Mynt 3D, and Novamaker-were used with the 3D pen. Heatmap analysis showed differentiation among these brands based on the liberated VOCs. The nozzle temperature and printing speed were found to affect the number and amount of released VOCs. This study goes a step further and presents for the first time a comparison between 3D pen and a desktop 3D printer based on liberated VOCs. Interestingly, the findings reveal that the 3D pen releases a greater number and amount of VOCs compared to the printer. The amounts of liberated VOCs, as indicated by the corresponding chromatographic peak areas, were found to be 1.4 to 62.6 times higher for the 3D pen compared to the 3D printer when using SPME Arrow.

Dilute-and-shoot approach combined with in-situ formed metal-containing ionic liquids for extraction of benzophenone and related compounds from açaí-based food products.

For the first time, benzophenone and related compounds were investigated in açaí-based food products. An extraction method based on the dilute-and-shoot approach, combined with the use of in-situ formed metal-containing ionic liquids (MCILs) followed by high-performance liquid chromatography, was developed and validated. A nickel and cobalt-based MCIL, in addition to the ratio of MCIL to lithium bis[(trifluoromethyl)sulfonyl]imide salt ([Li+][NTf2-]) for the ensuing metathesis reaction, were optimized. Parameters of the in-situ formed MCIL step, namely, the amount of MCIL, centrifugation time, and dilution step, were analyzed using a multivariate optimization approach, including central composite rotatable design and Derringer and Suich's tool. Optimum extraction performance was achieved using 50.98 mg of nickel-based MCIL and a MCIL to ([Li+][NTf2-]) ratio of 1:3 (m/m), a centrifuge time of 22 min, and 10.53 mL of water for the dilution step. This condition was used to perform analytical validation, which yielded satisfactory results with R2 ≥ 0.995, limits of detection (LOD) ranging from 0.0025 to 0.5 mg kg-1, and limits of quantification (LOQ) between 0.008 and 1.5 mg kg-1. The recovery rate ranged from 87 % to 107 % and precision values (as percent relative standard deviation) were equal or lower than 13 %. The validated method was applied to 25 samples of açaí-based food products purchased from Brazil and the United States. None of the samples showed analyte concentration levels above the LOD. The method's suitability was demonstrated for future monitoring of complex samples, such as foodstuffs.

Elucidating the role of temperature and water on the π-complexation strength of copper(I) ion-containing ionic liquids using inverse gas chromatography.

BACKGROUND: The π-complexation capability of copper(I) ion has been exploited in olefin/paraffin separations, but its propensity of undergoing disproportionation to copper(II) ion and copper metal has limited its use. Imidazolium-based ionic liquids (ILs) can serve as solvents for copper(I) ions as they facilitate copper(I) ion-olefin complexation and can enhance its stability. To precisely monitor how copper(I) ions complex with olefins in ILs and evaluate the effects of environmental factors, it is necessary to construct an experimental platform capable of quantitatively measuring their molecular-level interactions. RESULTS: This study employs an innovative inverse chromatography platform to measure changes in molecular-level interactions between copper(I) ions and olefins when the temperature and water content in the system are carefully controlled. Gas chromatographic stationary phases comprised of the 1-decyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C10MIM+][NTf2-]) IL containing 0.5 M [Cu+][NTf2-] were pre-heated to 140 °C maximizing copper(I) ion's π-complexation capability. The chromatographic retention of alkenes, dienes, and alkynes on the copper(I) ion/IL stationary phase was observed to be predominantly influenced by their partitioning between the carrier gas and copper(I) ion as well as between the IL and copper(I) ion. Upon introducing water to the system, the Gibbs free energy of solvation for olefins showed less favorable solvation into the stationary phase. In contrast, their solvation was significantly enhanced when the [Cu+][NTf2-]/[C10MIM+][NTf2-] stationary phase was heated to an elevated temperature, indicating that the π-complexation capability of copper(I) ion can be regenerated as needed. SIGNIFICANCE: This study demonstrates that the stability of copper(I) ions can be improved by dissolving them into appropriate IL solvents. Moreover, the olefin separation performance of the copper(I) ion/IL stationary phase was found to be adjustable by the application of different column treatment conditions (i.e., heating and water introduction), opening the possibility of devising more stable, reliable, and efficient olefin separation systems based on copper(I) ion and IL solvents.

Polymeric ionic liquid sorbent coatings in thin film microextraction: Insight into sorbent selectivity for pesticides and cannabinoids.

Polymeric ionic liquid (PIL) sorbent coatings consisting of polymerizable cations and anions were employed as sorbent coatings in thin film microextraction (TFME) for the extraction of pesticides and cannabinoids. The blades consisted of a thin film of PIL sorbents chemically bonded to vinyltrimethoxysilane-functionalized nitinol sheets. The imidazolium- or ammonium-based PIL sorbents contained aromatic benzyl moieties as well as polar hydroxyl groups or aliphatic functional groups within the chemical structure of the IL monomer. The chemical structure of the IL crosslinkers of the PILs were kept constant across each sorbent, except for the anion, which consisted of either bis[(trifluoromethyl)sulfonyl]imide ([NTf2-]), p-styrenesulfonate ([SS-]), or 3-sulfopropyl acrylate ([SPA-]). Temperature, salt content, and methanol content were optimized as extraction conditions to maximize pesticide-cannabinoid selectivity using Doehlert design of experiments (DOE). Effects of these three factors on selectivity and extraction efficiency are discussed. The optimal extraction conditions consisting of sample temperature (31°C), sodium chloride (30% w/v), and methanol content (0.25% v/v) are compared to initial sorbent screening conditions at a sample temperature of 40°C, 15% (w/v) sodium chloride, and 2.5% (v/v) methanol content. PIL sorbent swelling behavior at different salt and methanol content conditions and its effect on extraction efficiency are hypothesized. Selectivity factors for the sorbents indicated that aromatic moieties within the IL monomer may enhance pesticide-cannabinoid selectivity under optimized conditions, but the extraction efficiency of pesticides that are known to coelute with cannabinoids in the chromatographic separation may be enhanced by employing sorbent coatings with [SPA-] anions.

Ultrasound-assisted dispersive solid-liquid microextraction with eutectic solvents for the determination of cannabinoids in different hemp products.

The wide range of applications of hemp products, together with the environmental benefits that come from hemp cultivation are driving up the market demand for Cannabis sativa L. plant. One of the main restrictions for hemp cultivation and marketing concerns the content of delta-9-tetrahydrocannabidiol (Δ9-THC), which is known to have psychotomimetic effect. If the recent growing of hemp market is beneficial by an economic and environmental point of view, it is necessary to develop reliable analytical methods for the chemical characterization of hemp products, to guarantee the safety of use for the customers. This study aimed to develop a simple ultrasound-assisted dispersive solid-liquid microextraction (UA-DSLME) method for the extraction of cannabinoids in hemp products, using eutectic solvents (ESs) as extraction material. Two types of ESs were compared: one prepared with a [Ch+][Br-]-modified salts as hydrogen bond acceptor and one based on natural terpenoids. The ultrasound-assisted dispersive solid-liquid microextraction method was optimized to be applied for the analysis of aerial parts of hemp collected before flowering, hemp inflorescences and a commercial sample called CBD oil, and proved to be robust and versatile. Under optimal conditions, only 100 µL of ES and 2 mL of water as co-solvent were used in the US-assisted extraction, before the analysis in the UHPLC-PDA system. The developed approach allowed to obtain the same chemical profile of conventional methods, while improving the greenness of the method and the enrichment of the marker analytes. To overcome the strong matrix effect for cannabinoids, a matrix-matched calibration was used. Blank matrices of the samples under study were easily obtained by performing an exhaustive extraction of the marker analytes in the hemp samples. These matrices were successfully used for validation, achieving accuracy values between 82% and 118%.

Development of Allosteric NIK Ligands from Fragment-Based NMR Screening.

NF-κB inducing kinase (NIK) is vital for the induction of many immune responses, and as such, NIK dysregulation has been implicated in various inflammatory diseases and cancers. NIK has been pursued as a potential therapeutic target, and small-molecule inhibitors that bind the orthosteric site on NIK have been reported. However, despite the established chemical matter, NIK inhibitors have not yet reached the clinic. With the goal of developing allosteric NIK ligands using a fragment-based NMR screening approach, we report the identification and development of a series of allosteric, fragment-sized NIK ligands that bind with micromolar potency and good ligand efficiency.

Comparing π-complexation capabilities of ionic liquids containing silver(I) and copper(I) ions by headspace single drop microextraction in combination with high-performance liquid chromatography.

Selective π-complexation capabilities of silver(I) and copper(I) ions can be effectively facilitated in ionic liquids. To understand the effects of environmental factors that influence the π-complexation of these metal ions with analytes, techniques that employ small volumes of ionic liquid that can be readily analyzed are desired. In this study, headspace single drop microextraction coupled with HPLC is used to investigate a diverse set of environmental factors on the metal ion-mediated complexation with aromatic compounds in ionic liquid media. Silver(I) and copper(I) bis[(trifluoromethyl)sulfonyl]imide salts were both studied by dissolving them in the 1-decyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ionic liquid and employing the mixture as extraction media for aromatic compounds. Water and acetonitrile within the sample solution were observed to interfere with the complexation of silver(I) ions and aromatic compounds, while ethylene glycol and triethylene glycol did not. The temperature and extraction times were optimized to fully facilitate the π-complexation capabilities of metal ions in ionic liquid media. Partition coefficients between the sample headspace and metal ion were determined using a three-phase equilibria model. Although no discernable difference in analyte partitioning between the headspace and ionic liquid solvent was observed, analyte partition coefficients to silver(I) ion tended to be greater compared to copper(I) ion.

Smartphone as a fluorescence detector for high-performance liquid chromatography.

BACKGROUND: Fluorescence detection is employed in high-performance liquid chromatography (HPLC) due to its high specificity and sensitivity. However, it is often limited by expensive components and bulkiness. Recently, advances in technology and electronics have led to the development of smartphones that can serve as portable recording, analysis, and monitoring tools. Smartphone-based detection provides advantages of cost effectiveness, rapid signal/data processing, and the display of results on a handhold monitor. The combination of smartphone-based detection with HPLC can offer unique features that are beneficial in overcoming limitations of commercial fluorescence detectors. (90) RESULTS: A miniaturized and low-cost HPLC fluorescence detector based on a smartphone is introduced for the detection of six fluorescent molecules. The smartphone is able to capture emitted fluorescence in video format while MATLAB code is used for data processing to provide chromatograms based on different detection channels. A custom designed double-channel flow cell was utilized to enable simultaneous detection of fluorescent compounds with different excitation wavelengths. The detector consists of a lab-made flow cell, monochromatic LEDs as the light source, 3D printed housing and connector box, fiber optic cables, and a smartphone. The effects of flow cell geometry, channel width and light slit diameter, as well as a comparison of different flow cell manufacturing techniques, are studied and discussed. The validated system was successfully applied to samples from diverse water sources, yielding spiking recoveries within the range of 91.7% and 109.7%. (141) SIGNIFICANCE: This study introduces the first smartphone-based fluorescence detector for HPLC with cost-effective and customizable flow cells, allowing for the simultaneous detection of fluorescent compounds with different excitation wavelengths and offering a potential solution for the analysis of co-eluting compounds. Beyond its user-friendly interface and low-cost, smartphone detection in HPLC provides tremendous opportunities in further miniaturizing chromatographic instrumentation while offering high sensitivity and can be expanded to other mechanisms of detection. (70).

Ultra-Low Viscosity and High Magnetic Susceptibility Magnetic Ionic Liquids Featuring Functionalized Diglycolic Acid Ester Rare-Earth and Transition Metal Chelates.

Magnetic ionic liquids (MILs) comprise a subcategory of ionic liquids (ILs) and contain a paramagnetic metal center allowing them to be readily manipulated by an external magnetic field. While MILs are popularly employed as solvents in catalysis, separations, and organic synthesis, most low viscosity combinations possess a hydrophilic character that limits their use in aqueous matrices. To date, no study has reported the synthesis and characterization of hydrophobic MILs with viscosities similar to those of hydrophilic MILs and organic solvents while simultaneously exhibiting enhanced magnetic and thermal properties. In this study, diglycolic acid esters are employed as ligands to chelate with paramagnetic metals to produce cations that are paired with metal chelates composed of hexafluoroacetylacetonate ligands to form MILs incorporating multiple metal centers in the cation and anion. Viscosity values below 31.6 cP were obtained for these solvents, the lowest ever reported for hydrophobic MILs. Solubilities in nonpolar solvents such as benzene were observed to be as high as 50% (w/v) MIL-to-solvent ratio while being insoluble in water at concentrations as low as 0.01% (w/v). Effective paramagnetic moment values for these solvents ranged from 5.33 to 15.56 Bohr magnetons (µB), with mixed metal MILs containing multiple lanthanides in the anion generally offering higher magnetic susceptibilities. MILs composed of ligands containing octyl substituents were found to possess thermal stabilities up to 190 °C. The synthetic strategies explored in this study exploit the highly tunable nature of the employed cation and anion pairs to design versatile ultra-low viscosity magnetoactive solvents that possess tremendous potential and applicability in liquid-liquid separation systems, catalysis, and microfluidics where the mechanical movement of the solvent can be easily facilitated using electromagnets.

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.

Understanding the influence of polymeric ionic liquid sorbent coating substituents on cannabinoid and pesticide affinity in solid-phase microextraction.

To understand factors that drive pesticide-cannabinoid selectivity in solid-phase microextraction (SPME), eight new polymeric ionic liquid (PIL) sorbent coatings were designed and compared to four previously reported PIL sorbent coatings for the extraction of pesticides. The four PIL sorbent coatings consisted of either vinylimidazolium or vinylbenzylimidazolium ILs with long alkyl chain substituents (i.e., -C8H17 or -C12H25) and bis[(trifluoromethyl)sulfonyl]imide ([NTf2-]) anions, from which the eight new PIL sorbent coatings were adapted. Modifications to the chemical structure of IL monomers and crosslinkers included incorporation of polymerizable p-styrenesulfonate or 3-sulfopropyl acrylate anions, the addition of aromatic moieties, and/or the addition of polar functional groups (i.e., -OH or -O- groups). A total of ten commonly regulated pesticides and six cannabinoids were examined in this study. The effect of salt on the solubility of pesticides and cannabinoids in aqueous solutions was assessed by determining their extraction efficiencies in the presence of varied methanol content. Differences in their solubilities appear to play a dominant role in enhancing pesticide-cannabinoid selectivity. The selectivity, represented as the ratio of pesticide total peak areas to cannabinoid total peak areas, also exhibited a moderate correlation to the affinity of the sorbent coatings towards both the pesticides and the cannabinoids. A positive correlation was observed for the pesticides and a negative correlation was observed for the cannabinoids, suggesting that selectivity was driven by more than the presence of salt in the samples. The sorbent coatings' affinity towards each class of analytes were examined to determine specific interactions that might influence selectivity. The two main structural modifications increasing pesticide-cannabinoid selectivity included the absence of aromatic moieties and the addition of hydrogen bond donor functional groups. Extractions of simple aromatic molecules as probes were performed under similar extraction conditions as the cannabinoids and confirmed the influence of hydrogen bonding interactions on sorbent coating affinity.

Versatile dual-channel loop-mediated isothermal amplification assay featuring smartphone imaging enables determination of fecal indicator bacteria in environmental waters.

Rapid diagnostic assays are often a critical tool for monitoring water quality in developing and developed countries. Conventional testing requires 24-48 h for incubation, resulting in delayed remediation and increasing the likelihood of negative outcomes. In this study, we report a workflow for detection of E. coli, a common indicator of fecal contamination. Following large volume filtration, E. coli is then solubilized enabling the facile isolation and recovery of genetic material by a thin film microextraction (TFME) device featuring a polymeric ionic liquid (PIL) sorbent. Rapid recovery of pure nucleic acids is achieved using a PIL sorbent with high affinity for DNA to significantly increase mass transfer and facilitate adsorption and desorption of DNA. Downstream detection is performed by a versatile, dual channel loop mediated isothermal amplification (LAMP) assay featuring a colorimetric dye and a sequence-specific molecular beacon. A portable LAMP companion box enables consistent isothermal heating and endpoint smartphone imaging while being powered by a single 12-V battery. Programmable LEDs are switched from white or blue light to facilitate the independent imaging of the colorimetric dye or fluorometric probe following amplification. The methodology positively identified E. coli in environmental samples spiked to concentrations of 6600 colony forming units (CFU) per milliliter and 660 CFU/mL with 100% and 22% positivity, respectively.

Silver-mediated separations: A comprehensive review on advancements of argentation chromatography, facilitated transport membranes, and solid-phase extraction techniques and their applications.

The use of silver(I) ions in chemical separations, also known as argentation separations, is a powerful approach for the selective separation and analysis of many natural and synthetic organic compounds. In this review, a comprehensive discussion of the most common argentation separation techniques, including argentation-liquid chromatography (Ag-LC), argentation-gas chromatography (Ag-GC), argentation-facilitated transport membranes (Ag-FTMs), and argentation-solid phase extraction (Ag-SPE) is provided. For each of these techniques, notable advancements, optimized separations, and innovative applications are discussed. The review begins with an explanation of the fundamental chemistry underlying argentation separations, mainly the reversible π-complexation between silver(I) ions and carbon-carbon double bonds. Within Ag-LC, the use of silver(I) ions in thin-layer chromatography, high-performance liquid chromatography, as well as preparative LC are explored. This discussion focuses on how silver(I) ions are employed in the stationary and mobile phase to separate unsaturated compounds. For Ag-GC and Ag-FTMs, different silver compounds and supporting media are discussed, often with relation to olefin-paraffin separations. Ag-SPE has been widely employed for the selective extraction of unsaturated compounds from complex matrices in sample preparation. This comprehensive review of Ag-LC, Ag-GC, Ag-FTMs, and Ag-SPE techniques emphasizes the immense potential of argentation separations in separations science and serves as a valuable resource for researchers seeking to learn, optimize, and utilize argentation separations.

New Class of Tunable Choline Bromide-Based Hydrophobic Deep Eutectic Solvents for the Extraction of Bioactive Compounds of Varying Polarity from a Plant Matrix.

Deep eutectic solvents (DESs) are a class of sustainable solvents that have found numerous applications in different fields. One of their main attributes is the possibility of easily modifying their physicochemical properties by varying the type of hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA) that comprise them. Choline chloride ([Ch+][Cl-])-based hydrophilic DESs were among the first studied and the most used because of their capacity to easily create a hydrogen bonding network that lies in its unique chemical structure, characterized by a hydroxyl substituent within the ammonium headgroup. In this study, a new class of hydrophobic [Ch+][Br-]-modified salts were synthesized to produce HBAs with similar properties to choline for the preparation of hydrophobic DESs. Six different [Ch+][Br-]-based HDESs were prepared and characterized in terms of hydrophobicity, viscosity, and solvation properties (hydrogen bonding, dispersion, dipolarity/polarizability, n-π, and π-π interactions). They were employed as solvents in a microextraction method for the determination of phytochemicals in Cannabis sativa L. plant. The extraction performance of the [Ch+][Br-]-based HDESs was compared to eutectic mixtures based on conventional hydrophobic HBAs, and the results revealed that the unique properties of [Ch+][Br-]-modified salts allowed for the extraction of both hydrophilic (i.e., flavonoids) and hydrophobic compounds (i.e., cannabinoids).

Multi-residue method to determine selected personal care products from five classes in fish based on miniaturized matrix solid-phase dispersion and solid-phase microextraction coupled to gas chromatography-mass spectrometry.

A method featuring matrix solid-phase dispersion combined with solid-phase microextraction coupled to gas chromatography-mass spectrometry was developed to determine parabens, musks, antimicrobials, UV filters, and an insect repellent in fish. Optimization and validation of the method was carried out on tilapia and salmon samples. Acceptable linearity (R2 > 0.97), precision (relative standard deviations < 13 %) and accuracy (recovery > 80 %) at two concentration levels for all analytes were obtained using both matrices. The limits of detection ranged from 0.01 to 1.01 µg g-1 (wet weight) for all analytes except for methyl paraben. The SPME Arrow format was applied to increase the sensitivity of the method, and yielded detection limits more than ten times lower than those achieved with traditional SPME. The miniaturized method can be applied to various fish species, regardless of their lipid content, and represents a useful tool for quality control and food safety purposes.

Quantification of capture efficiency, purity, and single-cell isolation in the recovery of circulating melanoma cells from peripheral blood by dielectrophoresis.

This paper describes a dielectrophoretic method for selection of circulating melanoma cells (CMCs), which lack reliable identifying surface antigens and are extremely rare in blood. This platform captures CMCs individually by dielectrophoresis (DEP) at an array of wireless bipolar electrodes (BPEs) aligned to overlying nanoliter-scale chambers, which isolate each cell for subsequent on-chip single-cell analysis. To determine the best conditions to employ for CMC isolation in this DEP-BPE platform, the static and dynamic dielectrophoretic response of established melanoma cell lines, melanoma cells from patient-derived xenografts (PDX) and peripheral blood mononuclear cells (PBMCs) were evaluated as a function of frequency using two established DEP platforms. Further, PBMCs derived from patients with advanced melanoma were compared with those from healthy controls. The results of this evaluation reveal that each DEP method requires a distinct frequency to achieve capture of melanoma cells and that the distribution of dielectric properties of PBMCs is more broadly varied in and among patients versus healthy controls. Based on this evaluation, we conclude that 50 kHz provides the highest capture efficiency on our DEP-BPE platform while maintaining a low rate of capture of unwanted PBMCs. We further quantified the efficiency of single-cell capture on the DEP-BPE platform and found that the efficiency diminished beyond around 25% chamber occupancy, thereby informing the minimum array size that is required. Importantly, the capture efficiency of the DEP-BPE platform for melanoma cells when using optimized conditions matched the performance predicted by our analysis. Finally, isolation of melanoma cells from contrived (spike-in) and clinical samples on our platform using optimized conditions was demonstrated. The capture and individual isolation of CMCs, confirmed by post-capture labeling, from patient-derived samples suggests the potential of this platform for clinical application.

Comparison of olefin/paraffin separation by ionic liquid and polymeric ionic liquid stationary phases containing silver(I) ion using one-dimensional and multidimensional gas chromatography.

Silver(I) ions have been used in various studies as components within polymer membranes or ionic liquids (ILs) to enable separation of olefins from paraffins. Polymeric ionic liquids (PILs) are a class of polymers synthesized from IL monomers and typically possess higher thermal and chemical stability than the ILs from which they are formed. Until now, very little is known about the difference in strength of silver(I) ion-olefin interactions when they take place in an IL compared to a PIL. In this work, the chromatographic separation of olefins by stationary phases composed of silver(I) bis[(trifluoromethyl)sulfonyl]imide ([Ag+][NTf2-]) incorporated into the 1-hexyl-3-methylimidazolium NTf2 ([HMIM+][NTf2-]) IL and poly(1-hexyl-3-vinylimidazolium NTf2) (poly([HVIM+][NTf2-])) PIL at varying concentrations was investigated. Olefins were more highly retained by silver(I) ions in PILs than in ILs as the silver(I) salt concentration in the stationary was increased. The potential separation power of silver(I)-containing IL and PIL stationary phases in comprehensive two-dimensional gas chromatography (GC×GC) was compared to the conventional one-dimensional system. The separation selectivity of alkenes and alkynes from paraffins was significantly increased, while dienes and aromatic compounds showed insignificant changes in retention. The chemical structural features of IL and PIL that enhance silver(I) ion stability and olefin separation were investigated by using silver(I) trifluoromethanesulfonate ([Ag+][OTf-]), 1-decyl-3-methylimidazolium NTf2 ([DMIM+][NTf2-]) IL, poly(1-decyl-3-vinylimidazolium NTf2 (poly([DVIM+][NTf2-])) PIL, [HMIM+][OTf-] IL and poly([HVIM+][OTf-]) PIL. Longer alkyl substituents appended to the IL (and PIL) cation increased the strength of silver(I) olefin interaction, and [OTf-] anions in the IL (and PIL) tended to preserve silver(I) ion from thermal reduction, while also retaining olefins less than the [NTf2-]-containing columns. In general, silver(I) ions in PILs possessing analogous chemical structures to ILs exhibited higher silver(I) ion-olefin interaction strength but were less thermally stable.