Liquid-liquid Extraction Research Articles

Validated UPLC-MS/MS method for quantification of melatonin receptor agonists and dual orexin receptor antagonists in human plasma and breast milk: Application to quantify suvorexant and lemborexant in clinical samples

Pharmaceutical care is important for mental health during the perinatal period, which is often characterized by insomnia. In recent years, prescriptions of melatonin receptor agonists (MRAs) and dual orexin receptor antagonists (DORAs) for insomnia have increased; however, their use during the perinatal period has scarcely been reported. In the present study, we developed a UPLC-MS/MS method for the quantification of ramelteon, its metabolite M-II, suvorexant, and lemborexant in human plasma and breast milk to accumulate information on the safety and transfer of MRAs and DORAs into breast milk. Samples of MRAs (ramelteon and M-II) in plasma and breast milk were prepared using liquid–liquid extraction (LLE) with ethyl acetate. For DORAs (suvorexant and lemborexant), LLE with ethyl acetate was applied to plasma samples. For breast milk samples, significant ion suppression was observed for LLE with ethyl acetate. Solid-phase extraction (SPE) cartridges capable of removing phospholipids improved the matrix effects. Finally, protein precipitation with methanol and an SPE cartridge, InertSep® Phospholipid Remover, were selected for breast milk sample preparation. An ACQUITY UPLC BEH C18 column was used for analyte separation. MRAs and DORAs were eluted using isocratic and gradient elution, respectively, and analyzed using electrospray ionization in the positive mode with multiple reaction monitoring. The range of calibration curve for MRAs and DORAs was 0.1–25 and 0.5–50 ng/ml, respectively. Both the plasma and breast milk samples exhibited good linearity over this range. The method was validated by evaluating its accuracy and precision, matrix effect, recovery, carry-over, stability, and dilution integrity. The validated method was successfully applied to clinical samples donated by breastfeeding women and the milk/plasma (M/P) ratio and relative infant dose (RID) of lemborexant (one case) and suvorexant (two cases) were estimated. The M/P ratio of lemborexant was <1, and the RID was 1.05 %. The M/P ratio of suvorexant was <0.1, and RID was 0.11–0.20 %. This method will be useful for future studies evaluating the safety of these drugs during breastfeeding.

Variability in n-caprylate and n-caproate producing microbiomes in reactors with in-line product extraction.

Medium-chain carboxylates (MCCs) are used in various industrial applications. These chemicals are typically extracted from palm oil, which is deemed not sustainable. Recent research has focused on microbial chain elongation using reactors to produce MCCs, such as n-caproate (C6) and n-caprylate (C8), from organic substrates such as wastes. Even though the production of n-caproate is relatively well-characterized, bacteria and metabolic pathways that are responsible for n-caprylate production are not. Here, three 5 L reactors with continuous membrane-based liquid-liquid extraction (i.e., pertraction) were fed ethanol and acetate and operated for an operating period of 234 days with different operating conditions. Metagenomic and metaproteomic analyses were employed. n-Caprylate production rates and reactor microbiomes differed between reactors even when operated similarly due to differences in H2 and O2 between the reactors. The complete reverse β-oxidation (RBOX) pathway was present and expressed by several bacterial species in the Clostridia class. Several Oscillibacter spp., including Oscillibacter valericigenes, were positively correlated with n-caprylate production rates, while Clostridium kluyveri was positively correlated with n-caproate production. Pseudoclavibacter caeni, which is a strictly aerobic bacterium, was abundant across all the operating periods, regardless of n-caprylate production rates. This study provides insight into microbiota that are associated with n-caprylate production in open-culture reactors and provides ideas for further work.IMPORTANCEMicrobial chain elongation pathways in open-culture biotechnology systems can be utilized to convert organic waste and industrial side streams into valuable industrial chemicals. Here, we investigated the microbiota and metabolic pathways that produce medium-chain carboxylates (MCCs), including n-caproate (C6) and n-caprylate (C8), in reactors with in-line product extraction. Although the reactors in this study were operated similarly, different microbial communities dominated and were responsible for chain elongation. We found that different microbiota were responsible for n-caproate or n-caprylate production, and this can inform engineers on how to operate the systems better. We also observed which changes in operating conditions steered the production toward and away from n-caprylate, but more work is necessary to ascertain a mechanistic understanding that could be predictive. This study provides pertinent research questions for future work.

Optimisation and validation of liquid-liquid extraction of aminoglycosides from foods of animal origin

ABSTRACT This study focused on evaluating and optimising the liquid-liquid extraction (LLE) method for the multi-residue analysis of seven AGs in bovine liver, meat, milk, and kidney in conjunction with liquid chromatography coupled to a quadrupole-Orbitrap high-resolution mass spectrometry (LC-Q-Orbitrap HRMS) for quantification. Of all the hydrophilic interaction liquid chromatography (HILIC) stationary phases tested, the ZIC-HILIC column yielded the best performance. The method was validated according to Commission Implementing Regulation (CIR) EU 2021/808, which encompassed various concentration ranges from 25–7500 µg/kg. The mean recoveries ranged from 79% for liver matrix to 87% for meat matrix, with coefficients of variation (CV) below 18%. The method exhibited excellent linearity, as indicated by correlation coefficients (R2) greater than 0.9903 across all tested matrices. The decision limit (CCα) and detection capability (CCβ) varied from 62 to 5984 µg/kg and 71 to 6471 µg/kg, respectively. The limits of detection (LOD) and quantification (LOQ) were established between 1 and 45 µg/kg, and 2 and 75 µg/kg, respectively. No AG residues were detected in the 120 samples that were collected from different local markets in Egypt using the developed analytical method.

Liquid-liquid equilibrium of the 1-butyl-3-methylimidazolium-based ionic liquids + sodium citrate + water systems at 298.15 K

Liquid-liquid extraction has long been the preferred option for process engineers to develop separation processes and it is used to separate and purify various biological products, metallic ions, colorants, pharmaceutical molecules, and small organic species. Ionic liquids (ILs) are special ecological solvents that can be used as possible substitutes for traditional organic solvents used for extraction and separation processes, becoming them more sustainable and safer. In combination with salts or inorganic polymers, they can form a liquid system of two phases, advantageous due to its wide polarity and viscosity. In this scenario, liquid–liquid equilibrium (LLE) data and phase diagrams for new aqueous two-phase systems containing ionic liquid ([BMIM][OH], [BMIM][Cl], [BMIM][Br]) (1) + sodium citrate (2) + water (3) were determined experimentally at 298.15 K. The ionic liquids were synthesized and characterized in the first part of the study. COSMO-RS was used as a tool to calculate polarity graphs of study molecules. In the second part, liquid–liquid equilibrium was studied using experimental measurements of the binodal curve and tie-lines, testing the quality of experimental data by mass balance, thermodynamic modeling using the NRTL model to correlate liquid–liquid equilibrium data and to do their phase stability. The accuracy of the model data results was verified by Gibbs energy topological mixing surface analysis and σ profiles. The experimental results indicated that the studied systems had type I liquid–liquid phase behavior. It was demonstrated that the ionic liquid [BMIM][OH] demonstrated better behavior to form Aqueous Two-Phase Systems mixed with sodium citrate and water. The results obtained by the thermodynamic modeling and stability with NRTL model weren’t satisfactory, because, besides the low deviations for the liquid phases compositions, the majority of calculated tie-lines was not tangent with the Gibbs surface, showing the limitations of the model for systems with electrolytes.

Phosphatidylethanol is a promising tool for screening alcohol consumption during pregnancy.

Prenatal alcohol exposure (PAE) is one of the leading causes of preventable developmental disabilities. A lack of objective screening methods results in an under-recognition of the phenomenon. Phosphatidylethanol (PEth) is a specific ethanol biomarker that reveals alcohol intake up to several weeks after alcohol use. So far, PEth has mostly been a tool for detecting moderate and heavy drinking. With lower PEth cut-offs, revealing even minor prenatal alcohol consumption is possible. We aimed to find out if a sensitive method for PEth analysis would give additional information about PAE and to assess the cut-off value for a positive alcohol result in prenatal screening. The study was an observational study of 3000 anonymous blood samples collected from the Helsinki University Hospital Diagnostic Center between June and September 2023. The Finnish Red Cross Blood Service received the samples originally for blood group typing and antibody screening as part of the prenatal blood screening program. We developed a sensitive PEth 16:0/18:1 analysis method using ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) equipment after liquid-liquid extraction of PEth from whole blood. The lower limit of quantification was 1 ng/mL. PEth was ≥2 ng/mL in 5.2% of the cases, ≥8 ng/mL in 2.0%, and ≥20 ng/mL in 1.0%. The detection time of PEth can be several weeks, especially with low PEth concentrations and after heavy alcohol consumption. It remained unknown whether the positive PEth tests resulted from drinking deliberately during pregnancy or before pregnancy recognition. We suggest adding PEth 16:0/18:1 to a routine prenatal blood screening program with a cut-off of 2 ng/mL-and in positive cases, clinical evaluation and retesting in 2-4 weeks. In clinical settings, information on gestational week and alcohol consumption before pregnancy is relevant and needs to be considered when interpreting low PEth concentrations.

Liquid–liquid extraction method for the gas chromatography – mass spectrometry analysis of volatile fatty acids in wastewater

ABSTRACT This study addresses the need to transition WWTPs from energy-intensive operations to carbon-neutral and energy-efficient systems by examining VFAs’ concentrations, which vary significantly with different types of wastewater. The analytical performance of the liquid–liquid extraction (LLE) method using two solvents – methyl-tert-butyl ether (MTBE) and dichloromethane (DCM) – followed by injection into a gas chromatography-mass spectrometry (GC-MS) system is evaluated. The limit of quantification (LOQ) and limit of detection (LOD) for VFAs ranged from 3 to 7.41 mg/L and 0.91 to 2.25 mg/L, respectively. Precision for lower VFAs (ethanoic (C2), propanoic (C3), 2-methyl-propanoic (iC4), butanoic (C4), methyl-butanoic (iC5), and pentanoic acids (C5)) using DCM and MTBE ranged from 1.99% to 8.64% and 1.21% to 6.68%, respectively, with accuracies of 90.35% to 107.27% and 81.55% to 105.96%, respectively. For higher VFAs (iC6, C6, and C7) using DCM, precision ranged from 18.44% to 27.06%, and accuracy ranged from 70.1% to 101.4%. In contrast, MTBE failed to detect VFAs iC6, C6, and C7. These findings underscore the importance of solvent selection in VFA analysis and its implications for optimising WWTP operations.

Presence, behaviour, and risk assessment of volatile methylsiloxanes in wastewater: A year-long comprehensive study within a wastewater treatment plant

The awareness of possible environmental hazards caused by the widespread global use of volatile methylsiloxanes (VMSs) in personal care products (PCPs) and industrial processes has been increasing. Sewage containing these compounds may reach wastewater treatment plants (WWTPs), which are hotspots of their release into the environment. The levels, distribution, and potential risks of VMSs were studied in an unprecedently comprehensive sampling strategy (four seasonal campaigns) along the water line of a WWTP: the main influent entrance (SA1), after the preliminary treatment (SA2), after the primary treatment (SA3) and after the secondary treatment (the treated effluent; SA4). This WWTP was selected as a representative of the conventional set up based on a secondary treatment, allowing a similar approach in numerous facilities worldwide. Seven VMSs (L3, L4, L5, D3, D4, D5, D6) were analysed in wastewater samples by a small-scale liquid-liquid extraction (LLE) protocol, followed by gas chromatography–mass spectrometry (GC–MS), and the cyclic VMSs were dominant at all sampling sites and in all seasons. Considering the whole year, the total VMSs ranged from 0.4 to 22.5 μg L−1 for SA1, 0.03 to 33.7 μg L−1 for SA2, below method detection limit (MDL) to 13.2 μg L−1 for SA3 and <MDL to 0.8 μg L−1 for SA4. D5 prevailed, together with D6 and D4. The mean VMS mass flows dropped from 119 g day−1 in SA1 to 1.9 g day−1 in SA4, resulting in high removal efficiencies from the water line (>98 %). According to the risk quotients (RQ), only 18 SA4 samples (32 %) presented a minimal risk to the receiving media (0.01 ≤ RQ < 0.1). However, considering the absence of a secondary treatment or a direct discharge without treatment, there may be a risk to the environment.

Correlating physico-chemical properties of analytes with Hansen solubility parameters of solvents using machine learning algorithm for predicting suitable extraction solvent

Artificial neural networks (ANNs) are biologically inspired algorithms designed to simulate the way in which the human brain processes information. In sample preparation for bioanalysis, liquid–liquid extraction (LLE) represents an important step with the extraction solvent selection is the key laborious step. In the current work, a robust and reliable ANNs model for LLE solvent prediction was generated which could predict the suitable solvent for analyte extraction. The developed ANNs model takes a set of chosen descriptors for the cited analyte as an input and predicts the corresponding Hansen solubility parameters of the suitable extraction solvent as a model output. Then, from the solvent combination’s appendix, the analyst can identify the proposed extraction solvents' combination for the cited analyte easily and efficiently. For the experimental validation of the model prediction capabilities, twenty structurally diverse drugs belonging to different pharmacological classes were extracted from human plasma. The extraction process was performed using the predicted extraction solvent combination for each drug and quantitively estimated by HPLC/UV methods to assess their extraction recovery. The developed LLE solvent prediction model is in- line with the global trend towards green chemistry since it limits the consumption of organic solvents.

Interfacial effect of coexisting salt cations on extraction of erbium using gas bubble-supported organic liquid membrane

The conventional understanding about the specific ion effect from the coexisting electrolyte salts on the extraction and separation of target metal ions during liquid-liquid solvent extraction cannot explain some abnormal phenomena when more than one kind of background ions coexisting in the aqueous feed solutions to be separated. In this work, the specific ion effect of coexisting ions, Mg2+ and Al3+ as the example here, on extraction of Er3+ ion was investigated using gas bubble-supported organic liquid membrane. A very interesting phenomenon was noticed that, the difference in Er3+ extraction percentage was only 11.7 % in the Er-Mg solution system with addition of Al3+ ions or not, while it could reach 18.0 % in that of Er-Al with addition of Mg2+ ions or not. When Mg2+ and Al3+ coexisted simultaneously in the feed solutions, their specific ion effect on improving the extraction percentage of Er3+ was not equal to the sum of that when only single Mg2+ or Al3+ exists, respectively. Furthermore, a thinner organic liquid membrane supported by gas bubbles was in favor of enhanced interfacial enrichment of Er3+ and its diffusion mass transfer near the interface. During gas bubble-supported organic liquid membrane extraction, Mg2+ ions exhibited more obvious specific ion effect due to a weaker interaction with P507 molecules. However, a stronger hydration ability of Al3+ than Mg2+ ions induces a stronger competition of Al3+ with P507 molecules. Therefore, the coexistence of Mg2+ and Al3+ ions could play a synergistic role in enhancing enrichment of Er3+ on the basis of the mutual interference from the synergistic specific ion effect of coexisting Al3+ and Mg2+ ions. The research helps thoroughly understand the regulation mechanism on the synergistic specific ion effect for selective extraction of specified ions from the complex solutions containing multiple coexisting background ions.

IMIDAZOLIUM-BASED IONIC LIQUIDS FOR THE SELECTIVE SEPARATION OF TOCOTRIENOL HOMOLOGUES FROM PALM FATTY ACID DISTILLATE VIA LIQUID-LIQUID EXTRACTION

Objective: Tocotrienols have now stepped into the limelight of vitamin E research and have proven to have some exceptional benefits that are not shared by their “older” tocopherol siblings. Unlike tocopherols, tocotrienols are able to inhibit cholesterol biosynthesis, have specific neuroprotective activities stronger antioxidant effects, antihypertensive and anti-cancer. The purpose of this study was to carry out selective separation of tocotrienols homologues from Palm Fatty Acid Distillate (PFAD) by liquid-liquid extraction, using Ionic liquids (ILs) as extractants in the presence of diluent. Methods: Four kinds of imidazolium-based ILs that used are 1-butyl-3-methylimidazolium chloride ([Bmim]Cl), 1-Butyl-3-methylimidazolium acetate ([Bmim]Ac), 1-Hexyl-3-methylimidazolium chloride ([Hmim]Cl) and 1-Ethyl-3-methylimidazolium chloride ([Emim]C]). The extraction is carried out by creating a two-phase system between ILs and PFAD in n-hexane. Quantification of extracted tocotrienols was performed using High-Performance liquid Chromatography (HPLC) with a C18 column, mobile phase methanol: water (97.5:2.5), flow rate 1 ml/min and Ultraviolet (UV) detector at 295 nm. Results: The results showed that the concentration (extraction efficiency) of tocotrienols extracted using ILs in order were [Bmim] Ac 1611.09 mg/Kg (75.41%) and [Hmim][Cl] 1603.39 mg/Kg (75.05%), [Bmim]Cl 1523.60 mg/Kg (71.32%) and [Emim]Cl 1174.24 mg/Kg (54.96%). Conclusion: [Bmim]Ac yielded the highest tocotrienols concentration and extraction efficiency.

Simultaneous quantification of icaritin and its novel 3-methylcarbamate prodrug in rat plasma using HPLC-MS/MS and its application to pharmacokinetic study.

A sensitive, rapid, and simple HPLC-MS/MS method was first developed and fully validated to determine the icaritin (ICT) and its novel 3-methylcarbamate prodrug (3N) simultaneously in rat plasma. Analytes were extracted from rat plasma using a liquid-liquid extraction (LLE) method. Chromatographic separation was performed on ACE Excel 2 C18-Amide column. Quantitation of analytes was conducted on an LCMS-8060 triple-quadrupole tandem mass spectrometer. The quantitation mode was the multiple reaction monitoring via positive electrospray ionization. The calibration curve was linear over the concentration range of 1 to 200 ng/ml for ICT with a correlation coefficient of r= 0.9950 and 1 to 400 ng/ml for 3N with a correlation coefficient of r= 0.9956. The intra-precision RSDs were ≤12% for ICT and 3N. The inter-day precision RSDs were ≤10% for ICT and 3N. The accuracy RE was between -2.6% and 7.8% for ICT and 3N. The average ICT, 3N and IS recoveries were 87.9%, 83.6%, and 84.3%. The plasma matrix of ICT and 3N complied with the guidelines. ICT and 3N were stable in rat plasma under various tested conditions. This work has been successfully applied to studying the pharmacokinetics of ICT and 3N.

Determination of tetracycline residues in potatoes and soil by LC-MS/MS: Method development, validation, and risk assessment

A method utilizing liquid-liquid extraction (LLE) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated according to the Commission Implementing Regulation (CIR) EU 2021/808 for quantifying four tetracyclines (TCs) in potatoes and soil. The method demonstrated recovery values ranging from 70 to 121% and precision (repeatability and within-laboratory reproducibility), with coefficient of variation (CV) values below 18% for all TCs in both matrices. The limits of quantification (LOQs) for the TCs ranged from 0.90 to 1.87 μg/kg in potatoes and from 0.68 to 1.25 μg/kg in soil. The decision limit (CCα) and detection capability (CCβ) ranged from 10.4 to 12.3 μg/kg and 11.9 to 14.3 μg/kg, respectively. Analysis of 538 potato and soil samples from Egyptian farms revealed a 13.2% occurrence of TC residues, with a higher frequency in soil (19.33%) than in potatoes (7.06%). Target hazard quotient (THQ) values indicated that TC residues in potatoes do not pose a health risk to Egyptian consumers.

Selective Metal Recovery: Innovating Leaching from Lfp-NMC Cathode Mixtures in Lithium-Ion Batteries

Lithium-ion batteries lie at the heart of the energy transition and electric mobility. In the coming years, numerous gigafactories and recycling plants will be constructed worldwide to produce and recycle batteries for electric vehicles. While recycling plants currently focus on batteries for electric vehicle, there will also be a need to develop the recycling industry for smaller batteries, such as those used in electric bicycles, a market that is rapidly expanding. The chemical processes required to recycle these batteries may not necessarily be the same as those for batteries in electric vehicle due to differences in the composition of the materials to be processed. For electric vehicles, the composition will be well established as the materials will mainly come from either NMC (LiNixMnyCozO2) or LFP (LiFePO4) technologies. However, for batteries in electric bicycle and electric scooter, the materials to be processed will be a mix of NMC and LFP technologies. Therefore, it will be necessary to develop a flexible process capable of extracting metals from the feed which the composition will vary. Furthermore, the hydrometallurgical processes used to treat these materials must be capable of recovering cobalt, nickel, manganese, and lithium despite the presence of varying and significant concentrations of iron, which is generally challenging in hydrometallurgy.This talk will demonstrate how we can take advantage of the physicochemistry of transition metals in the presence of phosphate to develop an effective leaching process that selectively dissolves cobalt, nickel, manganese, and lithium from mixtures of NMC and LFP, resulting in a sufficiently pure leachate to facilitate downstream purification steps through liquid-liquid extraction after leaching.

OREATE as a High Yield and Purity Electrochemical Process for Transition and Rare Earth Metal Recovery

Developing a process that can consistently convert transition and rare earth metal oxides to chemically pure metals in near quantitative yield will have significant impact in many levels, from fundamental science to national security-related applications. Traditional separation methods of lanthanides and actinides from aqueous media have been based on liquid-liquid extractions that have proven to be quite efficient, though they are expensive and require complex engineering. Likewise, separation by pyro-chemistry provides a good recovery performance but requires the use of high temperatures that adds technological difficulties to the process. An alternative method that has grown interest in the last few years is the utilization of the difference in the metals’ reduction potentials from ionic state to metallic state. However, this electrochemical approach requires more negative reduction potentials than hydrogen evolution, which requires a very challenging control of their electrolytic deposition onto solid cathodes.In recent years, our team at LANL has been working on the development of OREATE (Oxide Reduction by Electrochemical Amalgamation and Thermal Extraction). OREATE is a holistic electrochemical approach that involves an initial step wherein the metal oxide is dissolved and chlorinated into an acidic medium. The dissolved metal cation is then electrochemically amalgamated via reduction using a mercury pool cathode. Finally, mercury's high vapor pressure allows an easy thermal extraction process to obtain the metal. From the conceptual perspective and preliminary results, the OREATE process appears easier and simpler than traditional separation methods and is suitable for small- and large-scale preparation of high purity metals.The results obtained using Cerium (Ce) as a surrogate metal demonstrated near quantitative yield of the electrochemical amalgamation (yield > 99%), almost complete mercury recovery during the thermal extraction (Hg recovery > 99.5%), and high purity of the Ce metal product (purity > 99%). Moreover, a variety of system parameters such as the pH of the buffered solution, concentration of cerium, reduction potential, and temperature were explored to evaluate the effect that the scaling up of the OREATE process may have on reaction rate, current efficiency, process yield, and temperature management.

Advancements in Aqueous Two-Phase Systems for Enzyme Extraction, Purification, and Biotransformation.

In recent years, the increasing need for energy conservation and environmental protection has driven industries to explore more efficient and sustainable processes. Liquid-liquid extraction (LLE) is a common method used in various sectors for separating components of liquid mixtures. However, the traditional use of toxic solvents poses significant health and environmental risks, prompting the shift toward green solvents. This review deals with the principles, applications, and advantages of aqueous two-phase systems (ATPS) as an alternative to conventional LLE. ATPS, which typically utilize water and nontoxic components, offer significant benefits such as high purity and single-step biomolecule extraction. This paper explores the thermodynamic principles of ATPS, factors influencing enzyme partitioning, and recent advancements in the field. Specific emphasis is placed on the use of ATPS for enzyme extraction, showcasing its potential in improving yields and purity while minimizing environmental impact. The review also highlights the role of ionic liquids and deep eutectic solvents in enhancing the efficiency of ATPS, making them viable for industrial applications. The discussion extends to the challenges of integrating ATPS into biotransformation processes, including enzyme stability and process optimization. Through comprehensive analysis, this paper aims to provide insights into the future prospects of ATPS in sustainable industrial practices and biotechnological applications.

Continuous Liquid-Liquid Extraction of Medium-Chain Fatty Acids from Fermentation Broth Using Hollow-Fiber Membranes.

Medium-chain fatty acids (MCFAs; carbon-lengths: C6-C12) are high-value platform chemicals that serve a variety of industrial applications, including green antimicrobials, food ingredients, animal feed additives, cosmetics, fragrances, pharmaceuticals, and structured lipids. Currently, most MCFAs are produced from palm and coconut oil originating from Southeast Asia and South America. The conventional approach to harvesting palm and coconut fruits causes considerable ecological damage in these regions. Therefore, researchers are developing biological approaches (e.g., precision and open-culture fermentations) to generate MCFAs more sustainably using low-value substrates (e.g., methanol, ethanol, lactate) or organic wastes as feedstock. Microbial chain-elongation (CE) is a rapidly maturing open-culture fermentation platform that converts short-chain fatty acids (SCFAs; carbon lengths: C1-C5) into a subset of these MCFAs at industrially relevant rates. However, continuous in situ extraction of MCFA products is necessary not only to avoid product inhibition but also to facilitate the recovery of MCFAs in a pure and usable form.Liquid-liquid extraction (LLE) using hollow-fiber membranes and targeted extractant mixtures has proven a robust approach to selectively extract MCFA products from fermentation broths containing SCFAs. Here, the application of LLE for continuous MCFA removal is demonstrated using CE as the reference fermentation system and 3% (w/v) trioctylphosphine oxide in mineral oil as the extractant system. Fatty acids ranging from valeric acid (C5) to caprylic acid (C8) are selectively removed from SCFA-containing broths and concentrated to high titers in a semi-batch alkaline stripping solution for downstream processing.

Liquid-liquid extraction equilibrium study of vanadium(V) from nitrate medium by technical grade D2EHPA dissolved in kerosene

The extraction behaviour of vanadium (V) from nitric acid solutions was studied using technical grade D2EHPA in kerosene as an extractant. The effects of aqueous pH, the concentration of vanadium (V) and nitrate ion in the aqueous phase, and the concentration of D2EHPA in the organic phase were investigated. The extraction equilibration time was 30 min. Metal ion dependencies appeared non-ideal due to the non-constancy of the aqueous phase acidity and the equilibrium extractant concentration. Two types of extraction mechanisms originated from the study of pH dependency. The study conceded that the extraction of vanadium (V) occurred via ion exchange or chelation type of extraction when the pH(eq) &lt;2.50. On the other hand, the solvated ion-pair extraction mechanism occurs when the pH(eq) was above 2.50. The extractant dependencies showed that vanadium (V) species were extracted by one molecule of D2EHPA. The salting-out effect was observed from the effect of nitrate ion concentration. The effect of various types of diluents on vanadium (V) extraction with technical grade D2EHPA was studied; kerosene appeared to be a suitable diluent. The temperature dependence data revealed that the system was exothermic with the ΔH value of -12.34 kJ/mol. The loading capacity was 6.11 g vanadium (V) per 100 g extractant. The H2SO4 (0.5 mol/L) was the right stripping agent for the extracted species.

Development and validation of a novel 7α-hydroxy-4-cholesten-3-one (C4) liquid chromatography tandem mass spectrometry method and its utility to assess pre-analytical stability.

7α-Hydroxy-4-cholesten-3-one (C4) is the common intermediary of both primary bile acids. C4 is recommended by the British Society of Gastroenterology for the investigation of bile acid diarrhoea (BAD) in patients with chronic diarrhoea. This project aimed to develop and validate an assay to quantitate C4 in serum and assess the stability of C4 in unseparated blood. Accuracy was underpinned by calibrating to quantitative nuclear magnetic resonance analysis. C4 was analysed in a 96-well plate format with a deuterated C4 internal standard and liquid-liquid extraction. Validation followed the 2018 Food and Drug Administration guidelines. To assess C4 stability, healthy volunteers (n=12) donated 8 fasted samples each. Samples were incubated at 20 °C for up to 72 h and retrieved, centrifuged, aliquoted and frozen for storage at different time points prior to C4 analysis. The C4 method demonstrated excellent analytical performance and passed all validation criteria. The method was found to be accurate, precise, free from matrix effects and interference. After 72 h of delayed sample separation, C4concentration gradually declined by up to 14 % from baseline. However, the change was not significant for up to 12 h. We present a robust method of analysing serum C4, offering a convenient alternative to 75SeHCAT for BAD investigation. C4 was found to decline in unseparated blood over time; however, after 12 h the mean change was <5 % from baseline. Our results suggest C4 is suitable for collection from both primary and secondary care prior to gastroenterology referral.

Salting-out assisted liquid-liquid extraction for the simple and rapid determination of veterinary antibiotic residues in aquatic products by HPLC-MS/MS

Based on salting-out assisted liquid-liquid extraction (SALLE) and high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS), a simple, rapid pretreatment without complex clean-up for the determination of 22 veterinary drug residues in aquatic products was developed and validated. In order to improve the efficiency of the method, the key procedural parameters of SALLE were fabricated. Na2EDTA-Mcllvaine buffer/ACN was used as the extraction solvent, anhydrous MgSO4 and NaCl as the extraction salts. The relationship between extraction efficiency and logD was initially evaluated during the optimization process. This study was well validated in various aquatic samples such as bass, large yellow croaker, carp, and shrimp, the limits of detection (LOD) and accuracy for all compounds ranged from 0.5 to 1.0 μg/kg, 71.4% to 120%. This method has the advantages of rapidity, simplicity, low cost, and high efficiency, and has broad potential for risk monitoring and evaluation of veterinary antibiotics in aquatic products.

Eco-friendly solvent-based liquid-liquid extraction of phenolic acids from winery wastewater streams

This study proposes liquid-liquid extraction (LLE) for the recovery of phenolic acids from winery wastewater replacing common volatile organic compounds (VOCs) with environmentally friendly solvents. On one hand, terpenes (α-pinene and p-cymene) and terpenoids (eucalyptol and linalool) were selected as green solvents and compared to common VOCs (ethyl acetate or 1-butanol). On the other hand, gallic acid (GA), vanillic acid (VA), syringic acid (SA) and caffeic acid (CA) were selected as phenolic acids to be recovered. The extraction performance was evaluated under different operation conditions: solvent-to-feed ratio, initial concentration of phenolic acids and temperature.This work also evaluated the back-extraction whole process global recovery and solvent regeneration, by means of aqueous NaOH solution. Eucalyptol has shown the highest overall global extraction performance (21.07 % for GA, 93.21 % for VA, 78.79 % for SA, and 80.57 % for CA) and lower water solubility compared to the best performing VOC solvent (1-butanol). Therefore, eucalyptol can be a potential eco-friendly solvent to replace VOCs for sustainable phenolic acid recovery from winery wastewater. Finally, to ensure a clean water stream after the LLE, the traces of solvent were completely removed by electrooxidation with boron-doped diamond anode at a current density of 422.54 A/m2.