Ternary Solvent System Research Articles

Preparation of pure chitosan film using ternary solvents and its super absorbency

Chemical modification and graft copolymerization were commonly adopted to prepare super absorbent materials. However, physical microstructure of pure chitosan film was optimized to improve the water uptake capacity in this study. Chitosan films with micro-nanostructure were prepared by a ternary solvent system. The optimal process parameters are 1% acetic acid water solution: dioxane: dimethyl sulfoxide=90: 2.5: 7.5 (v/v/v) with chitosan concentration at 1.25% (w/v). The water uptake capacity of the chitosan film prepared under the optimal process parameters was 896g/g. The prepared chitosan films also exhibited high water uptake capacity in response to external stimuli such as temperature, pH and salt. This finding may provide another way for improving the water absorbency. The pure chitosan film may find potential applications especially in the fields of hygienic products and biomedicine due to its super water absorbency and nontoxicity.

Preparation of an aqueous graphitic ink for thermal drop-on-demand inkjet printing

A graphitic ink for thermal DOD inkjet printing was developed. Challenges to be met were related to the small size of the getting nozzle (20 μm), demanding high dispersion stability of submicron particles, as well as to the physical requirements of the printer. In addition, solvents potentially hazardous to human health were excluded a priori. These necessities led to the development of a ternary aqueous solvent system based on 2-propanol and monoethylene glycol, offering an environmental-friendly alternative to conventional graphene solvents. In addition, high flexibility in terms of physical properties (e.g. surface tension, viscosity, density) important for jetting is obtained. Size reduction and exfoliation, accomplished by wet-grinding of graphite in the presence of a surfactant, were followed by laser diffraction and XRD line broadening analyses, respectively. The separated graphitic colloids used for preparation of inks were composed of ca 30 layers of AB–stacked graphene flakes, as determined by line broadening analyses (XRD data). Jetting of an ink with a solid content of 0.3 mg/mL gave a thickness increase of ca. 25 nm/pass, as determined by FESEM. Electrical characterization evidenced the need to remove residual organic molecules to regain the electrical properties of the graphitic particles.

Homogeneous Liquid-Liquid Microextraction for Determination of Organophosphorus Pesticides in Environmental Water Samples Prior to Gas Chromatography-Flame Photometric Detection.

In this study, homogeneous liquid-liquid microextraction (HLLME) was developed for preconcentration and extraction of 15 organophosphorus pesticides (OPPs) from water samples coupling with gas chromatography followed by a flame photometric detector (HLLME-GC-FPD). In this method, OPPs were extracted by the homogeneous phase in a ternary solvent system (water/acetic acid/chloroform). The homogeneous solution was excluded by the addition of sodium hydroxide as a phase separator reagent and a cloudy solution was formed. After centrifugation (3 min at 5,000 rpm), the fine particles of extraction solvent (chloroform) were sedimented at the bottom of the conical test tube (10.0 ± 0.5 µL). Furthermore, 0.5 µL of the sedimented phase was injected into the GC for separation and determination of OPPs. Optimal results were obtained under the following conditions: volume of the extracting solvent (chloroform), 53 µL; volume of the consolute solvent (acetic acid), 0.76 mL and concentration of sodium hydroxide, 40% (w/v). Under the optimum conditions, the enrichment factors of (260-665), the extraction percent of 75.8-104%, the dynamic linear range of 0.03-300 µg L(-1) and the limits of detection of 0.004-0.03 µg L(-1) were obtained for the OPPs. This method was successfully applied for the extraction and determination of the OPPs in environmental water samples.

Preparation and hemostatic property of low molecular weight silk fibroin

Effective hemorrhage control becomes increasingly significant in today’s military and civilian trauma, while the topical hemostats currently available in market still have various disadvantages. In this study, three low molecular weight silk fibroins (LMSF) were prepared through hydrolysis of silk fibroin in a ternary solvent system of CaCl2/H2O/EtOH solution at different hydrolysis temperatures. Fourier transform infrared spectroscopy analysis showed that the content of β sheet structure in the LMSF decreased with the increase in hydrolysis temperature. The results of thromboelastographic and activated partial thromboplastin time methods showed that the LMSF hydrolyzed at 50 °C can significantly strengthen the coagulation in blood and activate the intrinsic pathway of coagulation cascade. In the murine hepatic injury model, the LMSF hydrolyzed at 50 °C can promote the blood clotting and decrease the blood loss and bleeding time. Based on these results, it can be suggested that the developed LMSF has the excellent hemostatic effect and may be a promising material in clinical hemostatic application.

Analysis and Sources of Polycyclic Aromatic Hydrocarbons in Soil and Plant Samples of a Coal Mining Area in Nigeria.

This study analysed coal, plant and soil samples collected from the vicinity of Okobo coal mine in Nigeria for Polycyclic aromatic hydrocarbons (PAHs) and evaluated the sources of the PAH contamination in the environmental samples. The environmental samples were extracted by sonication using a ternary solvent system and analysed for 16 PAHs by gas chromatography-mass spectrometry (GC-MS). The results of the analysis of the samples identified some of the target PAHs. The ranges of total concentrations (in mg/kg) of PAHs in the coal, plant and soil samples were, 0.00-0.04, 0.00-0.16 and 0.00-0.01 respectively. The evaluation of the results of the PAH analysis of the environmental samples using diagnostic ratios revealed that the PAHs in the soil samples were mainly of petrogenic origin, while those in plant samples indicated mixture of petrogenic and pyrolytic origins.

Preparation of Sesquiterpenoids from Tussilago farfara L. by High-speed Counter-current Chromatography.

Background:Sesquiterpenoids, such as tussilagone, has effects of raising blood pressure, antiplatelet aggregation, and anti-inflammation activities, which is regarded as index compound for quality control of Tussilago farfara L.Objective:This study was aimed to obtain an effective method for fast isolation of sesquiterpenoids from T. farfara L. by high-speed counter-current chromatography (HSCCC).Materials and Methods:A solvent optimization method for HSCCC was presented, i.e., the separation factors of compounds after the K values of solvent system should be investigated.Results:A ternary solvent system of n-hexane:methanol:water (5:8:2, v/v/v) was selected and applied for the HSCCC, and 56 mg of tussilagone (2) was isolated from T. farfara L., along with two other sesquiterpenoids 5.6 mg of 2,2-dimethyl-6-acetylchromanone (1) and 22 mg of 14-acetoxy-7 β-(3’-ethyl cis-crotonoyloxy)-lα-(2’-methylbutyryloxy)-notonipetranone (3) by HSCCC with high purities. Their chemical structures were elucidated by liquid chromatography-mass spectrometry and nuclear magnetic resonance experiments.Conclusion:These results offered an efficient strategy for preparation of potentially health-relevant phytochemicals from T. farfara L., which might be used for further chemical research and pharmacological studies by preparative HSCCC.SUMMARY The real separation efficiency has been verified by analytical HSCCC.A solvent optimization method for HSCCC was presented and applied to separate and prepare active compounds.A method for rapid and effective separation of target compound Tussilagone with high yield and purity from the flower buds of Tussilago farfara.Two other compounds 2,2-Dimethyl-6-acetylchromanone and 14-acetoxy-7β-(3’-ethyl cis-crotonoyloxy) -lα- (2’-methylbutyryloxy). notonipetranone hasbeen obtained with high purities from flower buds of Tussilago farfara. Abbreviations used: HSCCC: High-Speed Counter-Current Chromatography; LC-MS: Liquid Chromatograph-Mass Spectrometer; NMR: Nuclear Magnetic Resonance; TCM: Traditional Chinese Medicine; HPLC: High Performance Liquid Chromatography; ESI-MS: Electrospray Ionization Mass Spectrometry; PE: petroleum ether

Modifing ASTM standard method by using homogeneous liquid-liquid microextraction combined with fiber optic UV-vis spectrometery for a greener approach to determination of total phenols in water

New developed method based on official American Society for Testing and Materials (ASTM) standard method was used for determining phenolic compounds in water by using homogeneous liquid–liquid extraction (HLLE) and fiber optic-linear array detection spectrometers (FOLADS). HLLE is a method based on phase separation in a ternary solvent system (water-tetrabutylammonium ion, TBA+-chloroform). The phase separation phenomenon occurred by an ion-pair formation of TBA+ and perchlorate ion. The aim of using this method was decreasing volume of extraction solvent used in ASTM standard method. After centrifugation the sediment phase was transferred to a 50-μL cylindrical micro-cell and absorbance was measured at 480 nm. Under the optimum conditions, linearity was obtained in the range of 5.0 to 80.0 μg/L for phenol. Coefficient of correlation (r2) was 0.992. The relative standard deviation was 1% for the analysis of 5 samples with concentration of 50 μg/L of phenol. The limit of detection was 2.0 μg/L. The relative recoveries of phenol in water samples were in the range of 97–104%. The proposed method was successfully applied for determination of phenolic compounds in real water samples.

A novel electrolyte used in high working voltage application for electrical double-layer capacitor using spiro-(1,1′)-bipyrrolidinium tetrafluoroborate in mixtures solvents

This paper is addressed on studying the electrolytes for electrical double layer capacitors with relatively high ionic conductivity and electrochemical stability for high energy density application. A systematic analysis of the electrochemical characteristics has been presented using spiro-(1,1′)-bipyrrolidinium tetrafluoroborate (SBP-BF4) with 1.5molL−1 (M) in variety of solvent compositions including propylene carbonate (PC), ethylene carbonate (EC) and dimethyl carbonate (DMC), while the solvent mixtures are PC+DMC (1:1 in volume) and PC+DMC+EC (1:1:1 in volume). The physical properties and electrochemical performance of SBP-BF4-based electrolytes are improved by tuning solvent mixtures compositions for high working voltage application. The binary solvent system of PC+DMC electrolyte exhibits lowest viscosity of about 3.14 mPas, while the ternary solvent system of PC+DMC+EC electrolyte exhibits highest conductivity of about 18.08mScm−1. The SBP-BF4/PC-based electrolytes display excellent upper voltage hold capability about 3.5V. The binary solvent system exhibits superior rate performance, when the charge cut-off voltage is lower than 3.2V. The ternary solvent system exhibits superior rate performance than that of other two solvent systems electrolytes, when the charge cut-off voltage is higher than 3.2V. The maximum energy density and power density of EDLCs using the ternary solvent system electrolyte are 41.5Whkg−1 and 17.0kWkg−1, respectively. The spiral cylindrical capacitors based on ternary solvent system electrolyte exhibits better cycle performance than that of other two solvent system electrolytes at the high working voltages.

Polymer Solar Cells: Solubility Controls Fiber Network Formation.

The photoactive layer of polymer solar cells is commonly processed from a four-component solution, containing a semiconducting polymer and a fullerene derivative dissolved in a solvent-cosolvent mixture. The nanoscale dimensions of the polymer-fullerene morphology that is formed upon drying determines the solar cell performance, but the fundamental processes that govern the size of the phase-separated polymer and fullerene domains are poorly understood. Here, we investigate morphology formation of an alternating copolymer of diketopyrrolopyrrole and a thiophene-phenyl-thiophene oligomer (PDPPTPT) with relatively long 2-decyltetradecyl (DT) side chains blended with [6,6]-phenyl-C71-butyric acid methyl ester. During solvent evaporation the polymer crystallizes into a fibrous network. The typical width of these fibers is analyzed by quantification of transmission electron microscopic images, and is mainly determined by the solubility of the polymer in the cosolvent and the molecular weight of the polymer. A higher molecular weight corresponds to a lower solubility and film processing results in a smaller fiber width. Surprisingly, the fiber width is not related to the drying rate or the amount of cosolvent. We have made solar cells with fiber widths ranging from 28 to 68 nm and found an inverse relation between fiber width and photocurrent. Finally, by mixing two cosolvents, we develop a ternary solvent system to tune the fiber width. We propose a model based on nucleation-and-growth which can explain these measurements. Our results show that the width of the semicrystalline polymer fibers is not the result of a frozen dynamical state, but determined by the nucleation induced by the polymer solubility.

Dispersive liquid-liquid microextraction: trends in the analysis of biological samples.

Dispersive liquid-liquid microextraction (DLLME) is a recent microextraction technique that was first developed by Rezaee and co-workers in 2006. It allows the simultaneous extraction and preconcentration of analytes into a micro-volume of extracting solvent based on a ternary solvent system involving an aqueous phase, a nonpolar water immiscible high-density solvent that acts as extraction phase, and a disperser solvent, which is often polar and water miscible. This article presents an overview of DLLME applications in the analysis of biological samples (e.g., plasma and urine). Aside from the classical DLLME applications using high density extraction solvents, recent advances in the use of low density solvents and ionic liquids are also discussed. Although most of the applications deal with the analysis of organic target compounds, a few applications on the bioanalysis of inorganic substances are also included.

Simultaneous Determination of Five Alkaloid Compounds in a Drug Based on a Hydrophilic Monolithic Column by Capillary Electrochromatography.

A novel capillary electrochromatography (CEC) method was developed by using a hydrophilic monolithic column for the simultaneous determination of five alkaloids in a drug. The monolithic stationary phase was first prepared via in situ polymerization of acrylamide (AM), glycidyl methacrylate (GMA), N,N'-methylenebisacrylamide (MBA) and 2-acrylamido-2-methyl-1-propane-sulfonic acid (AMPS) in a ternary porogen solvent system consisting of cyclohexanol, dodecanol and toluene. The obtained monolithic stationary phase was subsequently modified by 0.1 mol/L ammonia water for opening epoxide groups of GMA. The separation performance and efficiency of the resulting monolithic column were investigated by the use of five compounds (thiourea, aniline, naphthylamine, diphenylamine and dimethyl acetamide) by CEC. The optimized monolithic column has obtained high column efficiencies with 74,000-121,000 theoretical plates/m. Finally, the prepared monolithic column was used to separate and determine five alkaloids (piperine, nuciferine, kukoline, berberine and tetrandrine) using CEC. Under the conditions of acetonitrile/10 mM phosphate buffer solution (65/35, v/v, pH 8.5) and 15 kV applied voltage, the baseline separation of five alkaloids was achieved. The proposed method has been successfully applied to the determination of berberine in a tablet sample. The percentage of recovery of spiked tablet samples ranged from 93.4 to 108.0% with relative standard deviations (RSDs) <9.20%.

Phase equilibria and critical phenomena in the cesium nitrate-water-butyric acid ternary system at 5–100°C

The solubility, phase equilibria, and critical phenomena in the cesium nitrate-water-butyric acid ternary system, in which the boundary binary liquid system is not separated over the whole temperature range of its liquid state, were studied by the visual-polythermal method at 5–100°C. The temperature of formation of the critical node of the monotectic state (96.2°C) and the solution compositions corresponding to the critical points of solubility at different temperatures were determined. The distribution coefficients of butyric acid between the aqueous and organic phases of the monotectic state were calculated. The butyric acid salting-out from aqueous solutions with cesium nitrate insignificantly increased with temperature. The constructed phase state isotherms confirmed the fragment of the scheme of the topological transformation of the phase diagrams of the salt-binary solvent ternary systems with salting-in and salting-out.

High performance airbrush spray coated organic solar cells via tuning the surface tension and saturated vapor pressure of different ternary solvent systems

In this work, thieno [3,4-b] thiophene/benzodithiophene (PTB7): [6,6]-phenyl C71-butyric acid methyl ester (PC71BM) based organic solar cell (OSC) with a new record of power conversion efficiency (PCE) of ∼7.62% has been realized using airbrush spray (AS) coating method in air ambient which can be well compatible with large-scale fabrication. By investigating the physical mechanism of AS coated blend films, a series of ternary solvent systems (TSS) are used to simultaneous optimize the surface tension and the saturated vapor pressure of solution. Therefore, different TSS further controls the morphology of PTB7:PC71BM blend films precisely and systematically. It is elucidated that the chlorobenzene (CB)/o-Xylene (o-Xy)/1, 8-diiodoctane (DIO) TSS with a ratio of 37:60:3vol.% could lead to a homogeneous surface morphology with a decreased aggregation domain size of active layer. In addition, the high fill factor, increased PC71BM absorption and internal quantum efficiency indicate the formation of bicontinuous interpenetrating and fully percolated networks with nanostructured phase separation in BHJ blend films. Ultimately, the AS coated OSCs based on the TSS of CB/o-Xy/DIO gains a 34% enhancement in PCE, compared with the conventional CB/DIO solvent based OSCs.

Excellent low temperature performance electrolyte of spiro-(1,1′)-bipyrrolidinium tetrafluoroborate by tunable mixtures solvents for electric double layer capacitor

ABSTRACT This paper was addressed on studying the electrolyte for electrochemical double layer capacitors with relatively high ionic conductivity and high electrochemical stability for low temperature application. The data of systematical analysis of the electrochemical characteristics of EDLC have been presented using spiro-(1,1′)-bipyrrolidinium tetrafluoroborate (SBP-BF 4 ) with 1.5 mol L −1 (M) in a variety of solvent compositions including propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), while the mixture solvents are PC+DMC (1:1 in volume) and PC+DMC+EC (1:1:1 in volume). The physical properties and electrochemical performance of SBP-BF 4 in all solvent compositions are investigated. It is found that the binary solvent electrolyte systems exhibited better characteristics in electrochemical performance than single and ternary solvent system in low temperature. The capacitance of the binary solvent electrolyte systems could reach about 117.3 F g −1 at 20 °C and 92.3 F g −1 at −50 °C, which were higher than that of single and ternary solvent system. The energy density and power density of EDLCs based on binary solvents systems are can reach 29.6 Wh kg −1 and 12.5 kW kg −1 , respectively.

Designing New Conductive Imidazole-Derived Salt for Lithium-Ion Battery Electrolytes: A Computational Approach

Ever since the commercialization of the rechargeable Li-ion cell, LiPF6 is by far the most widely used electrolyte salt. It can produce electrolyte solutions with a superior ion conductivity, good electrochemical oxidation stability, and adequate thermal stability when dissolved in binary or ternary solvent systems of cyclic carbonates. However, LiPF6is also reported to have series problems that may lead to performance and safety issues (1). In order to circumvent these issues, researches have focused on designing new lithium salts which have thermal and electrochemical stability, high ionic conductivity and easy synthesis route (2-6). In this work, we report designing of an alternative salt derived from bis(trifluoroborane)imidazolide (LiIm(BF3)2) by employing density functional theory (DFT) calculations. New anion structures were generated by considering substitution at the C5 position with electron withdrawing groups (-F, -CF3, -SO3H and -NO2) and electron donating groups (-NH2, -OCH3 and –CH3). By using the optimized anion structures, random lithium ion-pair configurations (around 130 structures for each) were generated and optimized to identify the most stable configurations. The effects of different substituents were investigated with respect to ion dissociation energies, anion oxidative stability, and aromaticity of the molecules. Based on our calculations, we have found that, ion dissociation energies and intrinsic oxidative potentials of the anions were largely affected by the type of substituents introduced on the parent structure. Compared to –PF6 and -Im(BF3)2 (standard anions), –CF3 and -NO2 substituted anions showed an increase in anion oxidation stability. Since, BF3 occupies the strong Lewis basic sites of the imidazole ring, the parent structure itself exhibit a charge delocalization over the aromatic ring, which results in a weak coordinating ability with Li+. With the exception of –F, -CF3 and –CH3, further introduction of substituents at C5 position led to a much lower cation–anion interaction. Among the possible anions studied, 5-nitro-bis(trifluoroborane)imidazolide, with oxidation potentials > 5.7 V vs. Li+/Li , can be considered as a good candidates for high voltage Li-ion battery applications. Moreover, we have also found that the ion-pair dissociation energy, and anion stability of the selected salt are much improved compared to experimentally reported LiIm(BF3)2 and LiPF6.

Isolation of β-carotene, α-carotene and lutein from carrots by countercurrent chromatography with the solvent system modifier benzotrifluoride

A carotenoid purification method with dual-mode countercurrent chromatography (CCC) for β-carotene, α-carotene and lutein from a fresh carrot extract was developed. The fluorinated liquid benzotrifluoride (IUPAC name: (trifluoromethyl)benzene) was used as a novel modifier in the non-aqueous ternary solvent system n-hexane/benzotrifluoride/acetonitrile. The ternary phase diagram of the type I solvent system was used to select two-phase solvent mixtures which enabled an efficient preparative separation of α-carotene, β-carotene and lutein from concomitant pigments in crude carrot extract. By means of the modifier, high separation factors (α≥1.2) were obtained, allowing baseline resolution between α-carotene and β-carotene due to specific chemical interactions such as π–π molecular interactions. After optimizing the injection step with a pseudo-ternary phase diagram, 51mg of β-carotene, 32mg of α-carotene and 4mg of lutein could be isolated from 100.2mg crude carrot extract in a short time and with high purities of 95% and 99% by using dual-mode CCC, respectively. Temperatures >22°C had a negative impact on the separation of α-carotene and β-carotene.

Investigation of the Composition for a Ternary Solvent System in Tube Radial Distribution Chromatography

A tube radial distribution chromatography (TRDC) system was developed based on the tube radial distribution of a ternary solvent system. The composition for the water–hydrophilic organic solvent–hydrophobic organic solvent in TRDC was investigated using phase diagrams, chromatograms, and fluorescence photographs. Mixtures of a hydrophilic organic solvent (acetonitrile, ethanol, methanol, 1-propanol, or 1,4-dioxane) and a hydrophobic solvent (ethyl acetate, hexane, 1-butanol, or chloroform) were examined as the ternary solvent system, which was the carrier solution in TRDC. Water–acetonitrile–chloroform and water–acetonitrile–ethyl acetate systems performed well in TRDC. A model analyte solution of 1-naphthol (NA) and 2,6-naphthalenedisulfonic acid was separated by TRDC using the chloroform solvent system with a range of volume ratios for the solvent components. The elution order of these two compounds could be reversed by changing the solvent system from organic solvent rich to water rich. A mixture of five analytes, NA, Eosin Y, 1-naphthalenesulfonic acid, 2,6-naphthalenedisulfonic acid, and 1,3,6-naphthalenetrisulfonic acid, was also separated using the water–acetonitrile–chloroform solvent system (32:65:3 volume ratio). These compounds eluted in the order given above.

Template-free synthesis of complicated double-wall Cu2O hollow spheres with enhanced visible photocatalytic activities

In this study, complicated double-wall Cu2O hollow spheres have been successfully prepared by a facile hydrothermal process in a ternary solvent system including water, ethanol and glycerol.

Homogeneous liquid-liquid extraction coupled to ion mobility spectrometry for the determination of p-toluidine in water samples.

In this research, homogeneous liquid-liquid extraction followed by ion mobility spectrometry (HLLE-IMS) with corona discharge ionization source has been developed for the determination of p-toluidine. The analyte was extracted by single-phase extraction in a ternary solvent system and then the extracted p-toluidine was injected into IMS for analysis. Optimization of different parameters which could influence HLLE-IMS was performed. Under optimum conditions, the dynamic linear range was obtained over 2.0-40.0 ng/mL with R (2) = 0.9966 while relative standard deviation was below 10 %. The limits of detection and quantification were 0.6 and 2.0 ng/mL of p-toluidine, respectively. The proposed method was applied to determine p-toluidine in environmental water samples which resulted in acceptable recoveries of the analyte, ranging from 85.3 %-90 %.

Simultaneous quantification of eight bioactive secondary metabolites from Codonopsis ovata by validated high performance thin layer chromatography and their antioxidant profile

Chemical investigation of Codonopsis ovata resulted in the isolation and identification of β-sitosterol-3-O-glycoside, luteolin, apigenin, gentiacaulein, swertiaperenine, β-sitosterol, taraxeryl-3-acetate, and 3β-acetoxyoleanane-12-one. A rapid, precise, sensitive and validated HPTLC method for simultaneous quantification of these natural products (NPs) was developed on silica-gel 60F254 plate using ternary solvent system, n-hexane:ethyl acetate:formic acid (10.5:3.5:0.43, v/v/v). Markers were quantified after post chromatographic derivatization with cerric ammonium sulfate reagent. The method was validated for accuracy, precision, LOD, LOQ and all calibration curves showed a good linear relationship (r>0.9924) within test range. Precision was evaluated by intra- and inter-day tests with RSDs <2.59%, accuracy validation recovery 92.43–99.50% with RSDs <1.00%. Apigenin was found major component (natural abundance: 1.103%) and β-sitosterol the least (0.0263%). The NPs displayed antioxidant activity with luteolin exhibiting maximum effect at 1μg/mL concentration (75.9% for DPPH and 43.7% for ABTS) and others at 10 and 25μg/mL, suggesting thereby their apparent potential use for the prevention of free radical induced diseases or as an additive element to food and pharmaceutical industry.