Two-phase Solvent Extraction Research Articles

Direct Extraction and Determination of Free Nicotine in Cigarette Smoke.

The accurate determination of the free nicotine content in cigarette smoke is crucial for assessing cigarette quality, studying harm and addiction, and reducing tar levels. Currently, the determination of free nicotine in tobacco products primarily relies on methods such as pH calculation, nuclear magnetic resonance (NMR) spectroscopy, headspace solid-phase microextraction (HS-SPME), and traditional solvent extraction. However, these methods have limitations that restrict their widespread application. In this study, the free nicotine in cigarette smoke was directly extracted by using cyclohexane according to the traditional solvent extraction method and detected via gas chromatography-mass spectrometry. Compared with the traditional two-phase solvent extraction, our experimental method is easy to execute and eliminates the influence of aqueous solutions on the original distribution of nicotine in cigarette smoke particulate matter. Furthermore, the presence of protonated nicotine in tobacco does not affect the determination. Compared with HS-SPME and NMR spectroscopy, our approach, which involves solvent extraction followed by chromatographic separation and instrumental detection, offers simplicity, improved precision, better detection limits, and reduced interference during the instrumental detection stage. The standard addition recoveries in the conducted experiment ranged from 96.2% to 102.5%. The limit of detection was 2.8 μg/cig, and the correlation coefficient (R2) for the quadratic regression of the standard curve exceeded 0.999. The relative standard deviation for parallel samples was between 1.7% and 3.4% (n = 5), fully meeting the requirements for the determination of free nicotine in cigarette smoke. Analysis of cigarette samples from 38 commercially available brands revealed that the content of free nicotine ranged from 0.376 to 0.716 mg/cig, with an average of 0.540 mg/cig, and free nicotine accounted for 39.1%-88.8% of the total nicotine content.

Development of the production process of biodiesel from soy seed with cosolvent

Due to the expected depletion of the energy generated by non-renewable fuel sources, the development of biofuels is needed. This investigation proposed developing a process for biodiesel with two-phase solvent extraction technology. The seed fed in the process was extracted with Hexane, methanol, and water solution with a mass proportion of 3:5.4:1 (Hexane: methanol: oil) to separate the free fatty acids from the crude oil. The reaction happened with homogeneous alkali catalysis in the presence of Hexane (cosolvent). It used a molar ratio of methanol: oil of 6:1 and a mass ratio of 0.75% NaOH and 1.49 Hexane. After the purification, 0.941 kg of biodiesel per kg of oil fed to the process was obtained, and it meets the ANP regulations in some of the physicochemical proprieties. It also obtained 0.0985 kg of glycerine per kg of oil fed to the process with 99% purity.

D-limonene as an alternative for the extraction and purification of nuciferine from lotus leaf via multi-stage vortex assisted two-phase solvent extraction integrated with solid phase extraction using mesoporous material SBA-15 as adsorbent

This work aims to resolve the environmental pollution caused by petroleum ether in the production of pure nuciferine from lotus leaf by applying bio-based solvent (D-limonene) and green solvent (ethyl acetate). Some obvious advantages were observed, over 97% of nuciferine could be extracted by vortex assisted two-phase solvent extraction based on multi-stage strategy (MS-VTSE), over 90% of nuciferine could be recovered by solid phase extraction (SPE), and over 97% of nuciferine could be obtained by pH-dependent liquid-liquid extraction (pH-LLE). It follows that the newly developed method can not only avoid the use of petroleum ether, but also increase the yield of the whole process by 14% (57%) in comparing with the result of the original one (50%) reported in our previous study. As D-limonene could by recycled conveniently, solvents replacement has little effect on the cost of production. In a word, the newly proposed method has advantages in environmental protection and solvent saving, thus, is fitting for the green and low-cost production of pure nuciferine from lotus leaf.

Biodiesel production in a fixed bed reactor from Vernonia cinerea oil using calcined Pyrgostylus striatulus catalyst supported on activated carbon

ABSTRACT The current study had focused on continuous production of biodiesel from Vernonia cinerea seeds using a fixed bed reactor loaded with green catalyst. The free fatty acid (FFA) of the underexploited Vernonia cinerea seeds is very high. Two-phase solvent extraction (TPSE) methodology was implied for the extraction of oil to reduce the FFA and eliminate two-step transesterification process. At the experimental conditions of 60:40 n-hexane-to-methanol ratio, 65ºC temperature, and 4 hours of extraction time, 40% of Vernonia cinerea oil was obtained with FFA of 1.8%. The FFA of the oil got reduced by 78.5% by the implication of TPSE method. The characterization of the bio-oil was performed using FT-IR and GC-MS analysis. Pyrgostylus striatulus shells were calcined and supported on activated carbon. This was utilized as the green catalyst for biodiesel production. A complete analysis of the shells before and after calcination and after loading on activated carbon was studied using Hammett indicator, XRD, SEM, EDX, and BET analyses. Fixed bed reactor loaded with the calcined catalyst was utilized for the conversion of Vernonia cinerea oil and methanol into biodiesel. A maximum conversion of 96% was observed at the process conditions of 65ºC, 25:1 methanol-to-oil-molar ratio, 350-mm catalyst bed height and residence time of 6 hours. FT-IR analysis and 1HNMR analysis were performed to check the conversion of oil to biodiesel. The physio-chemical properties of methyl esters from Vernonia cinerea oil were analyzed. Findings of this research support that the produced biodiesel meets the ASTM standards indicating the fuel to be commercialized.

Electrochemical-Based Extraction, Separation, and Purification of Coumarin Compounds from Trifolium chinensis

In order to deal with the problems of the unstable transformation process and volatile palatability of coumarin compounds in C. chinensis, a method for the extraction, separation, and purification of coumarins in Chinese medicinal materials based on electrochemistry was prepared. First, an electrochemical distance-independent localization mechanism is used to determine node locations and routing mechanisms, and an extraction method is designed to achieve automatic and accurate real-time collection, aggregation, and transmission of ever-growing data. Environmental information for C. chinensis is collected. On the basis of this method, according to the chemical properties of coumarin and the extraction rate of coumarin as an index, the two-phase solvent extraction method and macroporous adsorption resin method were used to separate and purify it, and the best separation was determined. The purification process achieves efficient purification of coumarin. The experimental results show that the retention rate of coumarin by ethyl acetate is 34.5–56.8% higher than that of the other three extractants. When the optimal process determined in this study is adopted, the coumarin adsorption rate is greater than 98% and the recovery rate is greater than 85%. The purity of samples with 50% coumarin content can be increased to more than 97%, which verifies the correctness and advancement of the separation and purification process in this study.

Two-phase solvent extraction of phenolics from Origanum vulgare subsp. glandulosum

Integration of solid-liquid and liquid-liquid extractions, SLE and LLE, respectively, for selective recovery of Origanum vulgare subsp. glandulosum phenolics was studied. A Two-Phase Solvent Extraction (TPSE) was performed by maceration at room temperature using a green biphasic solvent system and compared to Centrifugal Partition Extraction (CPE). Up to 69 % of phenolics were similarly recovered by both CPE and TPSE techniques using the ethyl acetate/acetic acid/water solvent system (EAW) in immiscible proportions while only 56 % of purity was reached using the conventional successive technique. Up to 19 g GAE/100 g DW of total phenolics were recovered by solid-liquid-liquid extraction (SLLE) while only 12 g GAE/100 g DW was isolated by using SLE with EAW organic phase. Comparing TPSE to organic and aqueous macerations conducted separately, a clear positive impact of combination was observed, namely more than 57 % and 83 % enhancement of the extraction yields, respectively. Such extracts exhibited a very strong antioxidant activity as shown by the antioxidant activity index (AAI) higher than 2.

Comparative analysis of various processing on total phenolic content and antioxidant activity of flaxseed

Flaxseed, a minor oilseed possesses various biologically important components which makes it a potential food source. Along with its high nutritional quality, it has high antioxidant properties which protect human from various diseases. This study focused on analyzing and comparing the effect of different processes viz. soaking, roasting, mating, two-phase solvent extraction method, dehulling on the nutritional composition and biochemical properties (total phenolic content and antioxidant activity). Positive Pearson correlation was observed between crude protein & crude fiber (0.472) and negative correlation of crude fat with crude protein (0.56) & crude fiber (0.91). The TPC ranged from 354.82 to 748.3 GAE mg/100g while antioxidant activity ranged from 19.61% to 49.51%. Salt soaking methods slightly affected the TPC and AA while T4 significantly increased the both TPC and AA due to germination step. However, dehulling process exposed the flaxseed to damages from light and heat, thus significant reduction was observed.

In Situ Monitoring and Kinetic Analysis of the Extraction of Nitric Acid by Tributyl Phosphate in N-Dodecane Using Raman Spectroscopy

ABSTRACTUnderstanding the fundamental rates of transfer and complex formation is crucial in maintaining optimal efficiency and effectivity in solvent extraction. Methodologies to analyze solvent extraction systems are lacking in that they are commonly performed off-line in subsequent experiments. Thus, a method to proficiently investigate solvent extraction systems in a Lewis cell using in situ Raman spectroscopy paired with chemometric modeling has been developed to allow for on-line analysis and monitoring. Forward and reverse interfacial transfer coefficients for the extraction of nitric acid by tributyl phosphate, a process crucial to used nuclear fuel reprocessing, were measured by spectroscopic monitoring of both phases simultaneously in a two-phase solvent extraction system. Concentration data was derived from the chemometric modeling using Raman spectra. The concentration data was fit to a nonlinear least squares regression model to allow for the calculation of the transfer coefficients in the system. The reverse interfacial transfer coefficient, kr, was determined along with the parameter 95% confidence intervals and 95% prediction intervals. The forward interfacial transfer coefficient, kf, was then back calculated from kr and the aqueous phase and organic phase equilibrium concentrations. The average calculated values of kr and kf were 2.56 (± 0.50) × 10−5 m s−1 and 4.75 (± 1.13) × 10−6 m s−1, respectively. The information obtained regarding solvent extraction parameters and transfer can be applied in the study of systems of higher complexity, involving complex formation and their transfer across a liquid:liquid interface.

Online Coupling of Two-Phase Flow Solvent Extraction Microfluidics with Inductively Coupled Plasma Mass Spectrometry

Background: Recently, two-phase flow solvent extraction has been emerged as a promising method for the extraction of radionuclides because it enables minimized radiation exposure and little waste emission. In the field, the coupling of microfluidics-based solvent extraction and stripping with ICP-MS is expected because the combination enables highly sensitive and selective analysis. The previous works have successfully coupled only a single microchip with ICP-MS, leading to lack of selectivity and the need for handling radioactive materials during batch extraction. The study reports for the first time the successful coupling of combined extraction, stripping microchips with ICP-MS. Methods: Extraction of rhenium in 0.1 M HNO3 with Aliquat-336® and stripping of the resulting solvent by 8 M HNO3 were performed on Y-Y shaped microchannel chips. The condition for extraction and stripping in batches and on separate chips were characterized. Then two microchips were connected for extraction and back extraction in series. An external coiled tube (0.1 mm dia., 1 m long) was used to stabilize the pressure. As a result, two-phase flow could be maintained in both the microchips. Additionally, an interface system including a switching valve and a make-up flow was developed for coupling the solvent extraction chip with ICP-MS. The on-line measurement of Re after extraction and stripping was characterized. Results: The condition for extraction and stripping by combined microfluidic chips was found. The two-phase flow could be maintained for hour. The calibration curve of Re was obtained in the 1–20 µg/L range. The detection limit was 0.2 µg/L with a required sample volume of 1 mL. Total process time including extraction, back-extraction, and measurement was less than 1 h. The total efficiency using the combined microsystems was greater than 60%, while the total efficiency of separate extraction and back-extraction on microchips being about 40%. The interference is avoidable with the proposed combined system under the tested conditions. Conclusion: We successfully coupled combined microchips for extraction and stripping with ICP-MS. The two-phase flow can be formed and maintained for a long time through pressure balance by an external flow resistance (we used a coil tube in the study). The developed system promises a highly sensitive and selective elemental analysis with little direct treatment of samples, and thus it is possible to be applied in the field of radiochemical analysis. Keywords: Two-phase microflow, solvent extraction, ICP-MS, sequential analysis, elemental analysis, rhenium.

Synthesis of ditopic ligands for the selective extraction of copper(II) nitrate and crystal structures of their Cu(II) complexes

We have synthesized two ditopic ligands for selective extraction of copper(II) nitrate. We also synthesized one cation-only binding analog for comparison. All three ligands were characterized by conventional techniques. Competitive two-phase metal ion solvent extraction experiments were performed at 25 °C over a period of 24 h. These ligands showed significant selectivity for Cu(II) ions, having the ditopic ligands extract 81 and 73% of the Cu(II) ions in a solution of different metal ions {Ni(II), Co(II), Cu(II), Zn(II), Cd(II), Pb(II)} at pH 5.09. Competitive transport experiments (water/chloroform/water) were undertaken employing each ligand separately as the ionophore in the membrane (chloroform) phase. No metal ion transport was observed, but a large concentration of Cu(II) was present in the membrane phase. Competitive anion extraction and transport were carried out with the ditopic ligands, yielding selective extraction and transport of nitrate. Furthermore, a pH isotherm of the best ditopic ligand (H2L2) with Cu(II) was determined from pH 1.0 to 6.0, producing a pH½ value of approximately 2.6. Finally, crystal structures of the ditopic ligands complexed with Cu(II) were determined and refined. The coordination geometry around the metal centers are distorted square planar and the Cu(II)-donor bond lengths fall within the normal range.

Preparation of cottonseed‐based epoxy fatty acid methyl esters by an integrated approach

An integrated approach was developed for preparing epoxy fatty acid methyl esters (EFAMEs) from cottonseed using a two‐phase solvent extraction (TPSE) process followed by sequential base‐catalyzed transesterification and epoxidation reactions. The TPSE process was performed to achieve simultaneous production of high‐quality crude cottonseed oil and nontoxic cottonseed meal. The base‐catalyzed transesterification of the cottonseed oil proceeded smoothly at 30 °C over 2 h to provide a high yield of fatty acid methyl esters (FAMEs). Subsequent epoxidation of the unsaturated FAMEs using petroleum ether as a non‐polar solvent, H3PO4 as a catalyst, 0.3 g/g H2O2 as an oxygen donor, and HCOOH as an oxygen carrier gave the corresponding EFAMEs with a conversion to oxirane of 0.85 g/g. The order of effectiveness of catalysts was found to be H3PO4 > TiO2 > H2SO4 > strong‐acid cation exchange resin. The bio‐based integrated process and new methods for the preparation of modified EFAMEs show great promise for comprehensive development and commercial applications of cottonseed with fewer steps and lower cost.

Combined Production of Biodiesel and Nontoxic Cottonseed Meal Using Two‐Step Two‐Phase Solvent Extraction

AbstractThe preparation of biodiesel and nontoxic cottonseed meal from cottonseed by two‐step two‐phase solvent extraction (TS‐TSE) combined with the transesterification reaction was investigated. The TS‐TSE process could significantly reduce the biodiesel production costs when compared with the two‐phase solvent extraction (TSE) process due to the reduction in methanol. A series of experiments was conducted to evaluate the effects of some factors on the fatty acid methyl ester (FAME) yield and free gossypol (FG) content. These conditions resulted in a maximum FAME yield and reduced the FG content in the cottonseed meal far below the Food and Drug Administration standard. The nontoxic cottonseed meal could be used as animal feed protein source.

Calixarene-Mediated Liquid-Membrane Transport of Choline Conjugates.

A series of supramolecular calixarenes efficiently transport distinct molecular species through a liquid membrane when attached to a receptor-complementary choline handle. Calix-[6]arene hexacarboxylic acid was highly effective at transporting different target molecules against a pH gradient. Both carboxylic- and phosphonic-acid-functionalized calix[4]arenes effect transport without requiring a pH or ion gradient. NMR binding studies, two-phase solvent extraction, and three-phase transport experiments reveal the necessary and subtle parameters to effect the transport of molecules attached to a choline "handle". On the other hand, rescorin[4]arene cavitands, which have similar guest recognition profiles, did not transport guest molecules. These developments reveal new approaches towards attempting synthetic-receptor-mediated selective small-molecule transport in vesicular and cellular systems.

Simultaneous extraction of oil and soy isoflavones from soy sauce residue using ultrasonic-assisted two-phase solvent extraction technology

Simultaneous extraction of oil and soy isoflavones from soy sauce residue (SSR) was investigated by means of the two-phase solvent extraction intensified by ultrasonication. A single factor test was first carried out to study the effects of ultrasonic time, ethanol concentration, ratio of ethanol/water phase to raw material, ratio of hexane phase to raw material, and ultrasonic power on the extraction rates of oil and isoflavones, then response surface methodology was applied to further optimize and simulate four key factors. The results showed that the extraction rates of oil and isoflavones of 92.07% and 92.53%, respectively, could be obtained when ethanol concentration was 74.88%, ratio of ethanol/water phase to raw material 15:1, ratio of hexane phase to raw material 8.64:1, extraction time 20min, and ultrasonic power 160W. The predictive rates were well matched with the experimental ones. The quality analysis of oil and soy isoflavones from SSR showed that the extracted oil with high acid value could be a potential raw material for biodiesel production instead of cooking. The extracted soy isoflavones existed mainly in aglycones form, which might afford higher bioactivity than that from the other soybean products.

Simultaneous determination of red and yellow artificial food colourants and carotenoid pigments in food products

A method for simultaneously determining four artificial food colourants [Red Nos. 2 (R2) and 40 (R40), Yellow Nos. 5 (Y5) and 6 (Y6)] and three carotenoids [lycopene, lutein, and β-carotene] was developed. They were successfully separated by the developed high pressure liquid chromatography (HPLC) method combined with a photo diode array detector. The detection limit (at signal to noise>4) was from the lowest of 0.2ng/mL for lutein to the highest of 50.0ng/mL for R40. With a two-phase solvent and ultrasound-assisted extraction, the recoveries of the artificial and natural pigments in fifteen different types of food products were between 80.5–97.2% and 80.1–98.4%, respectively. This HPLC method with the ultrasound-assisted extraction protocol could be used as a sensitive and reliable analysis technique in simultaneously identifying and quantifying the reddish and yellowish pigments in different foods regardless of they are artificial food colourants or/and natural carotenoids.

Biodiesel Production of Garcinia Mangostana Linn. seeds by Two-Phase Solvent Extraction and Alkali-Catalyzed Transesterification

 Abstract—The present study introduced the potential used of Garcinia Mangostana Linn. seeds as feedstock for bio-diesel production. The preparation of biodiesel by two-phase solvent extraction (TSE) and alkali-catalyzed transesterification was studied. The important factors including catalyst concentration, ratio of methanol to oil and temperature on conversion FAME were examined respectively by experiments. The results of two-step transesterification showed that the optimal conversion of Garcinia Mangostana Linn. seeds into fatty acid methyl ester (FAME) were at condition of 4:1 methanol/oil volume ratio, 50 o C reaction temperature, 0.5% ( catalyst / oil weight ratio w/w) solid base catalyst amount and at 5 minutes reaction time.

Oil removal from waste coffee grounds using two-phase solvent extraction enhanced with ultrasonication

The objective of this study was to investigate the kinetics of ultrasound assisted-two phase oil extraction from waste coffee grounds with high moisture content. Waste coffee grounds is the wet residue which contains approximately 13% (db) oil. Ultrasound-assisted two-phase oil extraction method successfully extracted 98% of the available oil from the waste coffee grounds in 30 min. Ultrasonication reduced the amount of hexane used for the extraction. Fatty acid methyl ester compositions of the waste coffee oil and the soybean oil were similar. The kinetics of oil extraction from waste coffee grounds were modeled using a two-exponential mathematical equation. Establishing oil extraction facilities at locations where the ready-to-drink coffee products are produced and using two-phase oil extraction eliminate major challenges of collection, transportation and drying, which makes waste coffee grounds a viable feedstock for biodiesel production.

Alleviating monoterpene toxicity using a two‐phase extractive fermentation for the bioproduction of jet fuel mixtures in Saccharomyces cerevisiae

Monoterpenes are a diverse class of compounds with applications as flavors and fragrances, pharmaceuticals and more recently, jet fuels. Engineering biosynthetic pathways for monoterpene production in microbial hosts has received increasing attention. However, monoterpenes are highly toxic to many microorganisms including Saccharomyces cerevisiae, a widely used industrial biocatalyst. In this work, the minimum inhibitory concentration (MIC) for S. cerevisiae was determined for five monoterpenes: β-pinene, limonene, myrcene, γ-terpinene, and terpinolene (1.52, 0.44, 2.12, 0.70, 0.53 mM, respectively). Given the low MIC for all compounds tested, a liquid two-phase solvent extraction system to alleviate toxicity during fermentation was evaluated. Ten solvents were tested for biocompatibility, monoterpene distribution, phase separation, and price. The solvents dioctyl phthalate, dibutyl phthalate, isopropyl myristate, and farnesene showed greater than 100-fold increase in the MIC compared to the monoterpenes in a solvent-free system. In particular, the MIC for limonene in dibutyl phthalate showed a 702-fold (308 mM, 42.1 g L(-1) of limonene) improvement while cell viability was maintained above 90%, demonstrating that extractive fermentation is a suitable tool for the reduction of monoterpene toxicity. Finally, we estimated that a limonane to farnesane ratio of 1:9 has physicochemical properties similar to traditional Jet-A aviation fuel. Since farnesene is currently produced in S. cerevisiae, its use as a co-product and extractant for microbial terpene-based jet fuel production in a two-phase system offers an attractive bioprocessing option.

ChemInform Abstract: Metal Selectivity of Conformational Isomers Derived from p-t- Butylcalix(4)arene.

“Cone” and “partial cone” isomers of 25,27-bis(2-pyridylmethoxy)-26,28-bis(ethoxycarbonylmethoxy)-p-t-butylcalix[4]arene (3) were isolated by a TLC method and the structures were identified by 1H NMR. From two-phase solvent extraction of alkali picrates, the size of the ionophoric cavities was estimated to be in the order, partial-cone-3 > tetrakis(ethoxycarbonylmethoxy)-p-t-butylcalix[4]arene (cone) > cone-3. This is the first quantitative estimation of the ionophoricity of conformationally-isomeric calix[4]arenes.

Cogeneration of biodiesel and nontoxic cottonseed meal from cottonseed processed by two-phase solvent extraction

In the present work, the preparation of biodiesel from cottonseed oil produced by two-phase solvent extraction (TSE) was studied. The experimental results of TSE process of cottonseed showed that the optimal extraction conditions were 30 g samples, 240 mL extraction solvent mixture and methanol/petroleum ether volume ratio 60:40, extraction temperature 30 °C, extraction time 30 min. Under the extraction conditions, the extraction rate of cottonseed oil could achieve 98.3%, the free fatty acid (FFA) and water contents of cottonseed oil were reduced to 0.20% and 0.037%, respectively, which met the requirement of alkali-catalyzed transesterification. The free gossypol (FG) content in cottonseed meal produced from two-phase solvent extraction could reduce to 0.014% which was far below the FAO standard. And the nontoxic cottonseed meal could be used as animal protein feed resources. After the TSE process of cottonseed, the investigations were carried out on transesterification of methanol with oil–petroleum ether solution coming from TSE process in the presence of sodium hydroxide (CaO) as the solid base catalyst. The influences of weight ratio of petroleum ether to cottonseed oil, reaction temperature, molar ratio of methanol to oil, alkali catalyst amount and reaction time on cottonseed oil conversion were respectively investigated by mono-factor experiments. The conversion of cottonseed oil into fatty acid methyl ester (FAME) could achieve 98.6% with 3:1 petroleum ether/oil weight ratio, 65 °C reaction temperature, 9:1 methanol/oil mole ratio, 4% (catalyst/oil weight ratio, w/w) solid base catalyst amount and 3 h reaction time. The properties of FAME product prepared from cottonseed oil produced by two-phase solvent extraction met the ASTM specifications for biodiesel.