Liquid-liquid Extraction Research Articles

Enhancing Water Circularity: Lactic Acid-Menthol Deep Eutectic Solvent for Efficient Fats, Oils and Grease (FOG) Removal and Recovery from Contaminated Waters

Water pollution, particularly the contamination of water sources by fats, oils, and grease (FOG), presents a significant environmental challenge exacerbated by climate change. While conventional water resource recovery facilities (WRRFs) address various contaminants, FOG treatment often remains indirect and suboptimal. This study introduces an innovative, environmentally benign approach utilizing deep eutectic solvents (DESs) for the targeted removal and recovery of FOG from contaminated waters via liquid-liquid extraction. A binary DES comprising menthol and lactic acid was synthesized and evaluated for its efficacy in extracting oleic acid, selected as a model fatty acid contaminant. The investigation employed a comprehensive factorial design to optimize key operational parameters, including the molar ratio of DES components, solvent-to-water ratio, contact time, initial contaminant concentration, stirring speed, and phase separation time. Results demonstrated exceptional removal efficiencies exceeding 95% under optimized conditions, with peak performance approaching 99.5%. Optimal parameters were identified as a 1:1 molar ratio of menthol to lactic acid, 1:10 DES-to-water ratio, 15-minute contact time, 300 mg L⁻¹ initial contaminant concentration, 500 RPM stirring speed, and 8-hour phase separation. This research establishes a foundation for the application of DESs in water decontamination processes, potentially revolutionizing FOG management and advancing water circularity initiatives. The study's findings align with multiple UN Sustainable Development Goals, including SDG 6 (Clean Water and Sanitation), SDG 14 (Life Below Water), and SDG 12 (Responsible Consumption and Production), offering a promising avenue for sustainable water treatment technologies.

COSMO-RS prediction, experimental investigation, and mechanism analysis: A new approach to separating the n-hexane–tert-butanol azeotropic system via liquid-liquid extraction with ionic liquids

n-Hexane and tert-Butanol (TBA) are frequently utilized to refine the conditions for Grignard, Wittig, and Friedel-Crafts alkylation reactions. During the synthesis of loratadine, the formation of azeotropic mixtures n-hexane and TBA, which are challenging to separate through conventional distillation, is inevitable. This study utilizes the COSMO-RS model to identify suitable ionic liquids (ILs) for the separation of the n-hexane–TBA azeotropic system. Based on solvent capacity and selectivity, 1-ethyl-3-methylimidazolium trifluoroacetate ([EMIM][TFA]), 1-butyl-3-methylimidazolium trifluoroacetate ([BMIM][TFA]), and 1-hexyl-3-methylimidazolium trifluoroacetate ([HMIM][TFA]) were selected as extractants. The liquid–liquid equilibrium (LLE) data for the n-hexane–TBA – ILs ternary system were measured at 303.15 K and atmospheric pressure. Distribution coefficients and selectivity were calculated to evaluate the performance of the extractants, with the NRTL model used to correlate the experimental LLE data. The consistency of the NRTL model parameters was corroborated through topological analysis associated with the Gibbs tangent principle. Quantum chemical calculations, including interaction energy, ESP analysis, IGMH analysis, and QTAIM topological analysis, were performed to explore the separation mechanism at the molecular level. The results indicated that the interaction energies between the ILs and TBA were higher than those between the ILs and n-hexane, indicating a stronger attraction of ILs to TBA. Consequently, the ILs effectively separated TBA from the n-hexane–TBA azeotropic system, with extraction capacities ranked as [EMIM][TFA] > [BMIM][TFA] > [HMIM][TFA]. The quantum chemical calculations successfully explained the experimental results, aligning with COSMO-RS model predictions and confirming their reliability. IGMH and QTAIM topological analyses systematically explored the types and strengths of interactions, revealing that hydrogen bonds are predominant between the ILs and TBA, with additional contributions from van der Waals forces. Furthermore, the hydrogen bond strengths between TBA and the anions and cations of the ILs are classified as strong and moderate, respectively. This work provides valuable insights into the separation of azeotropic systems using ILs, elucidating the underlying mechanisms behind this process.

Redefining the waste: Sustainable management of olive mill waste for the recovery of phenolic compounds and organic acids

The olive oil industry generates significant amounts of olive mill waste (OMW), which poses environmental challenges due to its high organic load and phenolic content. This study investigates an eco-friendly approach to managing OMW by recovering valuable phenolic compounds (PCs) and volatile fatty acids (VFAs) through an integrated process. The methodology involves a filter press, followed by a self-cleaning mechanical vapor recompression (SCMVR) process for water and volatile compounds separation, and a subsequent liquid-liquid extraction for PCs. 99 % of the VFAs were recovered as organic acid salts from the SCMVR distillate and characterized using X-Ray diffraction (XRD) analysis. The Box-Behnken design (BBD) of response surface methodology (RSM) was used to optimize the extraction process, considering variables such as solvent type, pH, temperature, and extraction time. The liquid-liquid extraction process yielded a 98 % recovery of PCs with two-stage extraction process, including key phenolic species such as vanillic acid, caffeic acid, oleuropein, coumaric acid and gallic acid, identified by LC-MS/MS. This study highlights the potential for converting olive mill waste into valuable resources, promoting sustainable practices, and supporting a circular economy in the olive oil industry.

Enhancement and Validation of a Quantitative GC-MS Method for the Detection of ∆9-THC and THC-COOH in Postmortem Blood and Urine Samples

Cannabis is frequently detected in forensic investigations and is associated with an increased risk of fatal car crashes. This study aims to develop a method to detect and measure ∆9-tetrahydrocannabinol (∆9-THC) in blood and its metabolite, 11-nor-9-tetrahydrocannabinol-carboxylic acid (∆9-THC-COOH), in urine. The procedure employs two liquid-liquid extraction methods in conjunction with GC-MS in SIM mode. Both compounds were successfully processed, demonstrating the method's ease of use and efficiency. The method was validated for selectivity, identification capability, linearity, precision, limit of detection (LOD), limit of quantification (LOQ), and accuracy. Its effectiveness was further demonstrated by applying it to 30 authentic urine and blood samples from cannabis-related cases, establishing it as a valuable option for routine cannabinoid analysis in forensic toxicology labs.•The linearity range was 25–300 ng/mL for ∆9-THC in blood, and 50–300 ng/mL for ∆9-THC-COOH in urine, and calibration curves for both analytes showed R² values consistently above 0.989, confirming their linearity.•The LOD and LOQ for THC-COOH in hydrolyzed urine were 25 ng/mL and 50 ng/mL, respectively, and for THC in blood, they were 15 ng/mL and 25 ng/mL, respectively.•The variation coefficients were below 14%, and recoveries exceeded 81% for both compounds.

Phytochemical Profiling by HPLC-ESI-MS/MS and InVitro Investigation of the Antidiabetic Activity of Cassia bakeriana Bark Extract and Fractions.

Type 2 diabetes mellitus is a global health problem, placing patients at a higher risk of developing cardiovascular diseases and cancer. This study investigates the antidiabetic potential of Cassia bakeriana bark extracts and fractions. We evaluate their ability to inhibit α-amylase and α-glucosidase enzymes and advanced glycation end-products (AGEs). The antioxidant potential was also examined. Extracts were prepared through maceration with hexane (HE) and ethanol (EE), and the fractions were obtained via liquid-liquid extraction from EE. Anti-enzymatic, anti-glycation, antioxidant, and cytotoxic assays were conducted in 96-well plates using different concentrations of samples to determine the half-maximal inhibitory concentration (IC50). Active samples were further analyzed using HPLC-(-)-ESI-MS/MS. The ethyl acetate fraction (EAF) demonstrated a high percentage of α-amylase inhibition (94.0%) with a promising IC50 value of 1.05 μg mL-1. Additionally, EAF displayed 61.5% inhibition of α-glucosidase, with an IC50 value of 537 μg mL-1. The EE, EAF, and n-butanol fraction (BF) exhibited strong anti-glycation capacities. Furthermore, the EE, EAF, BF, and dichloromethane fractions showed promising antioxidant activity using the DPPH and ORAC methodologies. Cytotoxic activity was also evaluated with Vero cells, revealing no adverse effects on cell viability (CC50 > 512.0 μg mL-1). Active samples predominantly comprised proanthocyanidins, flavonoids, and anthraquinone, representing the main constituents of C. bakeriana bark. This study provides the first assessment of the antidiabetic potential of C. bakeriana bark and a comprehensive analysis of the chemical composition of its active extracts and fractions, offering hope for future treatments.

From historical drugs to present perils: UHPLC-QqQ-MS/MS determination of methaqualone and its designer analogs (NPS) with comprehensive fragmentation pathways study (QTOF)

Methaqualone, introduced in the 1960s as a sedative-hypnotic alternative to barbiturates, was withdrawn from the market due to its side effects and growing recreational use. Despite this, interest in methaqualone and its analogs remains high, raising concerns about potential abuse in the future. An ultra-high-performance liquid chromatography method coupled with triple quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS) was developed to determine nine methaqualone-related compounds simultaneously. Biological samples were prepared using liquid–liquid extraction with ethyl acetate at pH9; quantification was performed in blood using multiple reaction monitoring (MRM) mode. Methaqualone-d7 served as an internal standard. The limit of quantification (LOQ) ranged from 0.1 to 0.2 ng/mL, with precision and accuracy within 20%. Recovery ranged from 84.2% to 113.7%. The developed method allowed chromatographic separation of all compounds tested, including two structural isomers: methylmethaqualone and etaqualone. The mass spectra acquired from quadrupole time-of-flight mass spectrometer allowed for the elucidation of comprehensive fragmentation study of methaqualone derivatives. The described situation poses a significant problem from the analytical point of view, as well as interpretation and forensic toxicological expertise. The developed method will contribute to increased analytical capabilities and enhanced detection of compounds from the methaqualone group that may appear on the illicit market.

Signal Enhancement of Selected Norepinephrine Metabolites Extracted from Artificial Urine Samples by Capillary Electrophoretic Separation

The measurement of selected norepinephrine metabolites, such as 3,4-dihydroxyphenylglycol (DHPG), 3-methoxy-4-hydroxyphenylethylenglycol (MHPG), and vanillylmandelic acid (VMA), in biological matrices—including urine—is of great clinical importance for the diagnosis and monitoring of diseases. This fact has forced researchers to evaluate new analytical methodologies for their isolation and preconcentration from biological samples. In this study, the three most popular extraction techniques—liquid-liquid extraction (LLE), solid-phase extraction (SPE), and a new 3D-printed system for dispersive solid-phase extraction (3D-DSPE)—were investigated. Micellar electrokinetic chromatography (MEKC) with a diode array detector (DAD) at 200 nm wavelength was applied to the separation of analytes, allowing for the assessment of the extraction efficiency (R) and enrichment factor (EF) for the tested extraction types. The separation buffer (BGE) consisted of 5 mM sodium tetraborate decahydrate, 50 mM SDS, 15% (v/v) MeOH, 150 mM boric acid, and 1 mM of 1-hexyl-3-methylimidazolium chloride (the apparent pH of the BGE equaled 7.3). The EF for each extraction procedure was calculated with respect to standard mixtures of the analytes at the same concentration levels. The 3D-DSPE procedure, using DVB sorbent and acetone as the desorption solvent, proved to be the most effective approach for the simultaneous extraction and determination of the chosen compounds, achieving over 3-fold signal amplification for DHPG and MHPG and over 2-fold for VMA. Moreover, all extraction protocols used for the selected norepinephrine metabolites were estimated and discussed. It was also confirmed that the 3D-DSPE-MEKC approach could be considered an effective tool for sample pretreatment and separation of chosen endogenous analytes in urine samples.

Liquid-liquid extraction and separation of light and heavy rare earth elements from chloride solution using a mixture of tertiary amine and phosphinic acid: recycling strategies for NdFeB magnet

ABSTRACT This piece of work aims to study the extraction behavior of light and heavy rare earth elements, which are often found in permanent magnets, using a mixture of tri-octyl amine and bis-(2,4,4-trimethylpentyl) phosphinic acid from a chloride medium. The study showed that the extraction efficiency of Dy(III) is more than that of Nd(III) and Pr(III). Benzene proved to be an effective diluent. Increasing the pH of the aqueous phase improved the extraction percentages, with maximum extractions of 98.4% for Dy(III), 61.2% for Nd(III), and 58.3% for Pr(III) at pH 5.04 using 0.1 mol/L of each extractant. Adding sodium chloride enhanced the extraction efficiency due to the salting-out effect. The extraction mechanism has been proposed based on the slope analysis and FTIR data. From thermodynamic variables, the process was found to be exothermic. The simulated leach liquor of NdFeB magnets showed the highest separation factors of 67.7 (Dy/Pr) and 56.9 (Dy/Nd) at pH 2.05 with 0.25 mol/L extractants. The counter-current study showed that 4.15 mg/L Dy(III) was left behind in the raffinate indicating 97.4% removal of Dy(III) in two stages at unity phase ratio. Testing with actual leach liquor from hard disk magnets revealed a preference for iron extraction, which impeded REE extraction.

Sustainability assessment in food analysis: the application of Green Analytical Chemistry tools to phthalate residue analysis in edible oils

Edible oils are essential in daily diet due to their high contribution of fatty acids, fat-soluble vitamins, and triglycerides. During the processes of growing, processing, storage, transport, or packaging, they can be contaminated by ubiquitous phthalate esters, considered endocrine disruptors. Thus, analytical methodologies to allow tight control of their presence are mandatory. Several sample treatments have been considered in this study: microwave-assisted extraction (MAE), liquid-liquid extraction (LLE), dispersive solid phase extraction (DSPE), magnetic SPE (MSPE), solid phase microextraction (SPME), Surface-enhanced Raman spectroscopy (SERS) or its combinations. However, the selection of an analytical procedure is usually performed from an Analytical Chemistry perspective, without considering factors such as the sustainability of the selected methodology and/or its impact on the environment. In this sense, the Green Analytical Chemistry strategy can play an important role. To demonstrate this fact, six different analytical procedures have been evaluated in terms of sustainability by using several greenness evaluation tools. Procedures from MAE-gel permeation chromatography (GPC)-SPE till SERS, showing adequate analytical characteristics, have been selected. The application of Analytical GREEnness calculator (AGREE), AGREE preparation (AGREE prep), and blue applicability grade index (BAGI) tools showed that MAE-GPC-SPE was the less green analytical procedure while SERS was the greener one. The BAGI evaluation showed that headspace (HS) and SERS were the most applicable procedures.

Polarity Gradient Solvent Confinement Membrane Cartridge to Broaden Metabolite Coverage of Plasma Untargeted Analysis.

Various polarity chemicals exist in complex samples, such as plasma; nontargeted comprehensive analysis naturally requires multiple polar-extracted solvents; consequently, the polarity of the solvent plays a crucial role in the extraction efficiency of analytes from complex samples. In the present study, based on the diffusion behavior and nanoconfinement effect of solvents in the nanoconfined space, the polarity gradient solvent confinement liquid-phase nanoextraction (PGSC-NLPNE) protocol aimed to perform a one-step nontargeted analysis of a wide range of metabolites in plasma was established. The continuously wide range of extracted solvent polarities on carbon nanofibers/carbon fiber (CNFs/CF) membranes was achieved using a mixture of hexane, dichloromethane, methanol, and water as nanoconfined solvents. The polarities (Log P) of gradient solvents ranged from -1.38 to 3.94. Correlational analyses indicated that metabolites with Log P values ranging from -1.90 to 3.84 were closely related according to similarity-intermiscibility theory. Coupled with a homemade modified guard column device, CNFs/CF membrane cartridge (CCMC), a PGSC-NLPNE-UHPLC-MS online protocol was established and applied in plasma untargeted analysis. By comparing metabolome coverage, reproducibility, and extraction recovery with protein precipitation and two-step liquid-liquid extraction commonly used in untargeted analysis, the PGSC-NLPNE-CCMC protocol demonstrated higher reproducibility and recovery. This protocol has shown great potential for ultrafast analysis of plasma untargeted metabolomics with broader metabolome coverage. It could be a potential tool to rapidly screen out valuable biomarkers related to diseases in the clinic.

Fluorous and Organic Extraction Systems: A Comparison from the Perspectives of Coordination Structures, Interfaces, and Bulk Extraction Phases.

Microscopic structures in liquid-liquid extraction, such as structuration between extractants or extracted complexes in bulk organic phases and at interfaces, can influence macroscopic phenomena, such as the distribution behavior of solutes, including extraction efficiency and selectivity. In this study, we correlated the macroscopic behavior of the Zr(IV) extraction from nitric acid solutions with microscopic structural information to understand at the molecular level the key factors contributing to the higher metal ion extraction performance in the fluorous extraction system as compared to the analogous organic extraction system. The fluorous and organic extraction systems consist of tris(4,4,5,5,6,6,7,7,7-nonafluoroheptyl) phosphate (TFP) in perfluorohexane and tri-n-heptyl phosphate (THP) in n-hexane, respectively. Extended X-ray absorption fine structure, neutron reflectometry (NR), and small-angle neutron scattering revealed the structural information around the central metal ion of the complex, at the interface, and in the bulk extraction phase, respectively. NR results showed that extractant molecules did not accumulate much at the interface in both extraction system. In the fluorous extraction system, extractant aggregates with a 1.46 nm radius of gyration (Rg) were formed after contact with nitric acid, and remained even after Zr(IV) extraction through the form of a 1:3 (Zr(IV):TFP) complex. In contrast, in the organic extraction system, only extractant dimers with Rg of 0.70 nm were formed and Zr(IV) is extracted through the form of a 1:2 (Zr(IV):THP) complex. We speculate that differences in the local coordination structure around the Zr(IV) ion and the structuration of the extractant molecules in the bulk extraction phase contribute to the high Zr(IV) extraction performance in the fluorous extraction system. In particular, the size of the aggregates hardly changed with increasing Zr(IV) concentration in the fluorous phase, which may be closely related to the absence of phase splitting in the fluorous extraction system.

Influence of interface on nondeformable micropolar drop migration

Abstract In this article, an analytical approach is considered to study the issue of specifying Stokesian motion due to a micropolar sphere drop translating at a concentric instantaneous position within a spherical fluid–fluid interface that divides two immiscible fluids, one of which is bounded and the other is unbounded. Here, the focus is on the situation where there are two microstructure-related fluid phases (micropolar fluids) out of the three. The motion is considered to have low Reynolds numbers; thus, the drop’s surface and fluid–fluid interface have insignificant deformation. General solutions to the slow axisymmetric motion of the micropolar/viscous fluid in a spherical coordinate system are obtained based on a concentric position. Boundary conditions are fulfilled at the drop’s surface and the fluid–fluid interface. Findings indicate that the normalised hydrodynamic force increases monotonically as the droplet-to-interface radius ratio increases, acting on a moving micropolar sphere droplet and becoming unlimited when the drop’s surface touches the fluid–fluid interface. The numerical findings for the normalised force operating on the micropolar sphere droplet at different values of the suitable parameters are introduced in both graphical and tabular form. Our numerical findings are compared with the suitable data for the special cases stated in the literature. The current investigation of the study has practical applications in many domains of industrial, biological, medicinal, and natural processes, for example, liquid crystals, polymeric suspensions, muddy fluids, liquid–liquid extraction, raindrop formation, blood cells moving through a vein or artery, suspension rheology, sedimentation, and coagulation.

Efficient separation of methyl ethyl ketone and water azeotrope using hydrophobic amino acid ester ionic liquids

BackgroundMethyl ethyl ketone (MEK), an essential organic solvent, is commonly produced via the n-butene method, where water emerges as the principal impurity. The conventional distillation processes, which are necessitated by the azeotropic behavior between MEK and water, result in a substantial expenditure of energy. As a result, liquid-liquid extraction represents a promising alternative for energy-efficient separation. MethodsIn this work, three hydrophobic amino acid ester ionic liquids L-phenylalanine ethyl ester bis(trifluoromethylsulfonyl) imide ([Phe][NTf2]), L-leucine ethyl ester bis(trifluoromethylsulfonyl) imide ([Leu][NTf2]) and L-valine ethyl ester bis(trifluoromethylsulfonyl) imide ([Val][NTf2]) were utilized as extractants for separation of the binary azeotrope methyl ethyl ketone and water. The effects of extraction time, extraction temperature, mass ratio of MEK-water mixture to ionic liquid and initial concentration of MEK on extraction efficiency were investigated. Significant findingsThe results demonstrate that the ionic liquid [Phe][NTf2] exhibits superior extraction ability for the separation of the azeotrope methyl ethyl ketone and water. The maximum extraction yield of 99.86 % was achieved with the optimum extraction conditions of extraction time, 10 min, extraction temperature, 293.15 K, mass ratio of mixture to ionic liquid, 1:1 and initial concentration of MEK, 20 %. In addition, the relationship between the structure of ionic liquids and their extraction performance was revealed by quantum chemical calculations of ionic liquids with MEK and water. These ionic liquids were positioned as promising environmentally friendly alternatives to traditional organic solvents for the recovery of MEK from aqueous solutions, providing valuable insights for industrial applications.

Seasonal occurrence and ecological risk assessment of polycyclic aromatic hydrocarbons in the sediments and water in the left-bank canals of Indus River, Pakistan.

This study investigated a pressing environmental concern: the presence, distribution, sources, and ecological implications of sixteen polycyclic aromatic hydrocarbons (PAHs) in the left-bank canals of Kotri barrage-Akram, Pinyari, and Phuleli of the Indus River in Pakistan. These vital waterways, crucial for industrial, domestic, and agricultural activities, are experiencing contamination threats from anthropogenic sources, particularly PAHs. The study collected three water and two sediment samples from each canal in pre-monsoon and post-monsoon seasons. Then the EPA's liquid-liquid extraction method and gas chromatography determined the concentrations of PAHs. The findings of this study reveal alarming contamination levels, with pre-monsoon concentrations ranging from 22.256 to 836.455ng/L in water and 1,459.941 to 43,179.243ng/g in sediments. The post-monsoon concentrations ranged from 60.352 to 5663.058ng/L in water and 2976.770 to 15,238.335ng/g in sediments. The diagnostic ratios and principal component analysis (PCA) identified multiple sources of contamination, including industrial and domestic wastewater discharge, solid waste burning, vehicular emissions, biomass combustion, and petroleum residues. Furthermore, the assessment of the toxic equivalency factor (TEF) underscored the heightened carcinogenic potential of certain PAHs, notably benzo(a)pyrene and benzo(a)anthracene. Thus, the high levels of PAH contamination pose severe health risks to both human populations and aquatic ecosystems, emphasizing the urgency of addressing this issue. Stricter regulations governing industrial and domestic waste discharge, advocacy for cleaner fuel technologies, and the implementation of effective waste management practices must be initiated as crucial strategies in safeguarding the environmental integrity of the left-bank canals and the health of the surrounding communities.

Stoichiometric Lanthanide Compounds with Diglycolamides: A Synthetic Approach toward Understanding Rare-Earth Speciation in Solution.

A fundamental understanding of coordination chemistry across the lanthanide series is essential for explaining the chemical behavior of rare-earth metals in complex liquid-liquid extraction processes. Probing the exact bonding between the extractant and the metal is sometimes done through the synthesis of solid-state compounds that can serve as models for metal speciation in solution. In the case of diglycolamide (DGA), a commonly used neutral diamide extractant, extensive studies identify the stepwise formation of 1:1 [Ln(DGA)(H2O)6]3+, 1:2 [Ln(DGA)2(H2O)3]3+, and 1:3 [Ln(DGA)3]3+ complexes in solution. The crystallographic reports, however, exclusively show a 1:3 [Ln(DGA)3]3+ moiety in the solid state, while the structures of 1:1 and 1:2 complexes are yet to be isolated and comprehensively studied. In this work, we report the synthesis and characterization of three new families of stoichiometric N,N,N',N'-tetramethyldiglycolamide (TMDGA) compounds: [Ln(TMDGA)(H2O)5Cl]Cl2·2H2O, [Ln(TMDGA)2(H2O)3]Cl3·3H2O, and [Ln(TMDGA)3]Cl3·7H2O, where Ln = Nd, Eu, Gd, with Ln:TMDGA ratios of 1:1, 1:2, and 1:3, respectively. The compounds have been analyzed using vibrational spectroscopy (both Raman and FT-IR), as well as variable temperature fluorescence spectroscopy. A spectrophotometric titration of Eu(III) was performed to confirm the presence of the [Eu(TMDGA)n]3+ (n = 1, 2, and 3) species in solution and to compare the individual solid-state emission spectra to their respective analogues in solution.

An Efficient Fluorescent Chemosensing Probe for Total Determination and Speciation of Ultra-Trace Levels of Mercury (II) Species in Water.

The current study reports a novel fluorescent chemosensor based on the tagging agent 4,5,6,7-tetrachloro-2',4',5',7'-tetraiodofluorescein (Rose Bengal, RB) for detection of trace levels of Hg2+in environmental water. The established probe has been based upon liquid-liquid extraction (LLE) of the developed ternary complex ion associate {[Hg (bpy)2]2+.[RB]2-} of Hg2+ -2,2- bipyridyl complex [Hg (bpy)2]2+ and RB at pH 9.0 onto chloroform and measuring the resulting fluorescence enhancement signal intensity at λex/em = 570/ (580-600) nm. The limits of detection (LOD) and quantification (LOQ) of for Hg2+ was calculated to be 6.06 and 20 nM with a linear dynamic range (LDR) of 0.02-20µM, respectively. The stability constant, stoichiometry, chemical equilibria, and the thermodynamic parameters (ΔH, ΔS, and ΔG) of the developed ion associate were evaluated and assigned. Student's t and F tests at 95% confidence were fruitfully used for validation of the proposed methodology for Hg2+ detection in water samples with the aid of inductively coupled plasma-optical emission spectrometry (ICP-OES). The established strategy was successfully applied for detection of trace levels of Hg2+ in water samples with acceptable results. The proposed probe was satisfactorily applied for total determination and speciation of Hg in various water samples. Integrating the functional chelating agent onto associate formation to improve the selectivity and sensing properties of the LLE combining sensing probe towards target analyte in water represent the main interest.

Human Biomonitoring of Serum Polybrominated Diphenyl Ethers by Supported Liquid Extraction and Gas Chromatography Coupled With Tandem Mass Spectrometry.

This study aims to develop and validate a robust analytical method for the quantification of polybrominated diphenyl ethers (PBDEs) in human serum using gas chromatography-tandem mass spectrometry. We compared procedural blanks, recoveries, and operational convenience of liquid-liquid extraction and supported liquid extraction for the determination of serum PBDEs. We evaluated different extraction solvents for their effect on PBDE recoveries. Supported liquid extraction was selected for method validation due to its operational convenience. The method demonstrated satisfactory linearity, sensitivity, and reproducibility, with the range of 0.10-5.00µg/L for most PBDE congeners and 0.20-10.0µg/L for PBDE-154 and PBDE-183, with limits of detection ranging from 2 to 48ng/L, and with matrix effects ranging from 94% to 113%. Quality control assessments indicated that recoveries ranged from 85% to 110% and relative standard deviations of less than 11%. The proposed method was applied to biomonitoring of 111 healthy adults, revealing detectable levels of PBDEs in over 90% of the samples. BDE-47 and BDE-183 were the most prevalent, with mean concentrations of 4.13 and 22.1ng/L, respectively. Detection frequencies ranged from 0.90% for BDE-17 and BDE-85 to 25.2% for BDE-47. Males had higher mean concentrations of BDE-183 than females.

Determination of Total Flavonoid Content from Extract and Fractions of Mangrove Leaves (Rhizopora mucronata)

Indonesia is an archipelagic country with a very wide coastal area. Lombok Island has a coastal area with quite extensive mangrove forest areas. Rhizopora mucronata was the most dominant species found in the region. The Rhizopora mucronata species was a plant from the Rhizoporaceae family reported to have antibacterial, antifungal, and antioxidant activity. These biological activities were caused by the presence of secondary metabolite compounds in R. mucronata, one of which is flavonoids. Research regarding the flavonoid content of R. mucronata leaves has not been explored. Therefore, the study aimed to determine the total flavonoid content in extracts and fractions of R. mucronata leaves using the spectrophotometric UV-Vis method. R. mucronata mangrove leaves simplicia were extracted using the sonication method using 96% ethanol solvent, then fractionated using the liquid-liquid extraction method with n-hexane, ethyl acetate, and water. The percentage yield of 96% ethanol extract, water fraction, ethyl acetate fraction, and n-hexane fraction respectively were 42.33%; 43.147%; 40.49%; 9.74%; and 32.49%. The TLC test showed the presence of flavonoid compounds detected in the extract and fractions which were marked with blue spots. The total flavonoid contents in the 96% ethanol extract, water fraction, ethyl acetate fraction, and n-hexane fraction were respectively (12,980; 14,160; 23,880; and 25,350) mg Quercetin equivalent/gram sample (mg QE/ g). The total flavonoid content of the extract and fractions of R. mucronata leaves were analyzed using the One-way ANOVA test method. The total flavonoid content in the n-hexane fraction and ethyl acetate fraction was significantly higher than the 96% ethanol extract and water fraction. The total flavonoid content of R. mucronata leaves was relatively high, which contributes to several of its biological activities.

Online Direct Infusion Mass Spectrometry of Liquid–Liquid Extraction Phases for Metabolite and Lipid Profiling with the Direct Infusion Probe

Background/Objectives: Profiling of metabolites and lipids in biological samples can provide invaluable insights into life-sustaining chemical processes. The ability to detect both metabolites and lipids in the same sample can enhance these understandings and connect cellular dynamics. However, simultaneous detection of metabolites and lipids is generally hampered by chromatographic systems tailored to one molecular type. This void can be filled by direct infusion mass spectrometry (MS), where all ionizable molecules can be detected simultaneously. However, in direct infusion MS, the high chemical complexity of biological samples can introduce limitations in detectability due to matrix effects causing ionization suppression. Methods: Decreased sample complexity and increased detectability and molecular coverage was provided by combining our direct infusion probe (DIP) with liquid–liquid extraction (LLE) and directly sampling the different phases for direct infusion. Three commonly used LLE methods for separating lipids and metabolites were evaluated. Results: The butanol–methanol (BUME) method was found to be preferred since it provides high molecular coverage and have low solvent toxicity. The established BUME DIP-MS method was used as a fast and sensitive analysis tool to study chemical changes in insulin-secreting cells upon glucose stimulation. By analyzing the metabolome at distinct time points, down to 1-min apart, we found high dynamics of the intracellular metabolome. Conclusions: The rapid workflow with LLE DIP-MS enables higher sensitivity of phase separated metabolites and lipids. The application of BUME DIP-MS provides novel information on the dynamics of the intracellular metabolome of INS-1 during the two phases of insulin release for both metabolite and lipid classes.

Advancing Rare-Earth (4f) and Actinide (5f) Separation through Machine Learning and Automated High-Throughput Experiments.

Identifying improved and sustainable alternatives to "classic" separation techniques is an active research field due to its potential widespread impact in fundamental and applied chemistry. As basic purification methodologies, like liquid-liquid extraction, undergo continuous refinement by chemists and engineers, identifying new conditions that outperform existing techniques can be difficult. A major contributor to this challenging problem is the need to explore a vast experimental space to identify the precise conditions that optimize the separation procedure. The advent of artificial intelligence and the advancement of robotic technologies offer the potential to shift the traditional design paradigm. Toward that end, we applied a combination of Bayesian Optimization and high-throughput robotic experiments on the liquid-liquid extraction of thorium (Th4+) and demonstrated that this approach speeds up discovery and significantly accelerates the optimization process. By using Bayesian Optimization as a guide, our automated instrument carried out a total of 339 distribution ratio measurements, corresponding to 113 unique conditions, identifying the optimal experimental conditions with reduced experimental efforts by an estimated 74% compared to a traditional full screening approach. This time and cost saving is particularly significant for radioactive materials, as it not only is more economical and sustainable but also minimizes human exposure to radioactivity.