Mixture Of Chloroform Research Articles

DETERMINATION OF ANTIBIOTIC RESIDUES IN COW MILK BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY METHOD

Antibiotics are used as growth boosters, illness prevention and treatment in animal agriculture. The majority of cattle farmers take advantage of the system and do not adhere to the withdrawal periods. These antibiotics are identified as residues in ready-to-eat meat, causing negative consequences in human beings. The majority of the study on determining antibiotic residues in ready-to-eat meat relied on thorough research and paid little attention to animal products such as cow milk. The goal of this study was to use a method that could be used on a regular basis to determine the amounts of antibiotic residues in cow milk marketed to the general population in Ibadan. These antibiotics residues (chloramphenicol and erythromycin) were extracted from cow milk by centrifugation and liquid-liquid extraction using acetonitrile. Vacuum-liquid chromatography was used to clean the extracts, and 10mL of a 1:1:1 v/v mixture of n-hexane, chloroform, and methanol was used. After that, a high-resolution liquid chromatography analysis was performed on the extracts. All of the samples included residues of chloramphenicol (CAP), with mean values ranging from 91.4610.89 to 692.6616.74 ng/g, while erythromycin (ERY) was not observed. All of the samples contained chloramphenicol, proving that cow farmers had been abusing it.

Simultaneous Dispersive Liquid–Liquid Microextraction and Determination of Different Polycyclic Aromatic Hydrocarbons in Surface Water

Polycyclic aromatic hydrocarbons (PAHs) are a class of persistent organic pollutants of water, and their determination at trace levels in the aquatic ecosystems is essential. In this work, an ultrasound-assisted dispersive liquid-liquid microextraction (DLLME) procedure was suggested utilizing a binary dispersive agent for recovery of different molecular weight polycyclic aromatic hydrocarbons (PAHs) from waters. The detection was carried out by gas chromatography-mass spectrometry (GC-MS) as well as high-performance liquid chromatography with fluorescence and diode-array detection (HPLC-FD/PDA). The method was optimized for the extraction of analytes with respect to the mixture composition, ratios of components, ultrasonication time and centrifugation parameters. The analytical schemes for PAHs extraction from water samples using different ratios of extraction and dispersive solvents are reported. The mixture consisting of chloroform and methanol was applied for the extraction of PAHs containing two or three fused aromatic rings; the mixture of chloroform and acetonitrile is suitable for PAHs containing more than four aromatic rings. The mixture of chloroform:acetone + acetonitrile was applied in the universal scheme and allowed for the simultaneous extraction of 20 PAHs with different structures. The developed sample preparation schemes were combined with GC-MS and HPLC-FD/PDA, which allowed us to determine the analytes at low concentrations (from 0.0002 µg/L) with the recoveries exceeding 80% and relative standard deviations of about 8%. The developed methods for the determination of 20 PAHs were applied to the analysis of water samples from the Karasun Lake (Krasnodar), Azov Sea (Temryuk) and Black Sea (Sochi).

Integrated anaerobic-aerobic biodegradation of mixed chlorinated solvents by electrolysis coupled with groundwater circulation in a simulated aquifer.

Chlorinated solvents are widespread subsurface contaminants that are often present as complex mixtures. Complete biodegradation of mixed chlorinated solvents remains challenging because the optimal redox conditions for biodegradation of different chlorinated solvents differ significantly. In this study, anaerobic and aerobic conditions were integrated by electrolysis coupled with groundwater circulation for biodegradation of a mixture of chloroform (CF, 8.25mg/L), 1,2-dichloroethane (DCA, 7.01mg/L), and trichloroethylene (TCE, 4.56mg/L). A two-dimensional tank was filled with field sandy and silty-clayed sediments to simulate aquifer conditions, a pair of electrodes was installed between an injection well and abstraction well, and groundwater circulation transported cathodic H2 and anodic O2 to produce multiple redox conditions. Microbial community analysis demonstrated that the system constructed a habitat suitable for the co-existence of aerobic and anaerobic microbes. After 50days of treatment, 93.1%, 100%, and 87.3% of CF, 1,2-DCA, and TCE were removed without observed intermediates, respectively. Combined with compound specific isotope analysis, the degradation of 1,2-DCA and CF was mainly attributed to aerobic oxidation and reductive dechlorination, respectively, and TCE was removed by both aerobic and anaerobic biodegradation. Our findings provide a new and efficient strategy for in situ bioremediation of groundwater contaminated by mixed chlorinated solvents.

LC-MS/MS method for the determination of a semi-synthetic phenolic antioxidant 2,6-diisobornyl-4-methylphenol in rats after different administration routes

IBP (2,6-diisobornyl-4-methylphenol) is a small drug molecule with antioxidant properties considered to be a promising neuro-, cardio-, and retinoprotective agent. In this study, a bioanalytical LC-MS/MS method for its determination in rat plasma was developed using 11H-indeno[1,2-b]quinoxalin-11-one oxime as an internal standard (IS). The analytes were extracted from plasma by liquid–liquid extraction technique using isopropyl alcohol:chloroform mixture (1:5, v/v) followed by evaporation and reconstitution of the residues in acetonitrile. The chromatographic separation was carried out on the EC Nucleodur C8 ec column (150 × 4.6 mm, 5 μm) under an isocratic elution mode using acetonitrile and water containing 0.1% (v/v) formic acid (97:3, v/v) as a mobile phase at a flow rate of 0.55 mL/min (40 °C). The IS and IBP were eluted at 3.79 ± 0.02 and 6.30 ± 0.02 min, respectively. The total analysis time was 7.00 min. Multiple reaction monitoring was used to conduct the MS/MS detection in the negative ion mode with transitions at m/z 245.9 → 214.9 (IS) and 379.2 → 256.0 (IBP). Validation studies of the developed method revealed good linearity over the range of 10–5,000 ng/mL. Within- and between-run accuracy was in the range of 92–110%, while within- and between-run precision was below 8%. Additionally, low matrix effects and high recovery (above 98%) were observed. IBP remained stable in rat plasma at room temperature for 4 h, at −80 °C for 21 days, over three freeze–thaw cycles, under vacuum concentrator (45 °C, dried residues) and auto-sampler (15 °C, processed samples) temperatures for 1 h and 24 h, respectively. Subsequently, the validated LC-MS/MS method has been successfully applied to quantitate IBP in actual plasma samples after a single oral, intramuscular, and subcutaneous dose of IBP (10 mg/kg in the peach oil) to rats. Pharmacokinetic studies show that more rapid and complete IBP absorption with a satisfactory excretion rate were observed after oral administration route compared to the intramuscular and subcutaneous ones.

Genotoxic and antigenotoxic potential of encapsulated Enhalus acoroides (L. f.) Royle leaves extract against nickel nitrate

Several environmental pollutants can cause damage to chromosomes, one of which is the heavy metal NiNO3. Some plant extracts have antigenotoxic properties that result in a decrease in chromosomal damage. Member of flowering plants that need to be tested is seagrass. One seagrass species is Enhalus acoroides which was found to contain phytochemical compounds. This study aimed to analyse the genotoxic effect and the potential of encapsulated E. acoroides leaf extract as antigenotoxic against nickel nitrate NiNO3. The extraction was conducted using a mixture of chloroform and ethanol, and crude extract encapsulated using maltodextrin and tween 80. Chromosomal aberrations were evaluated using the squash technique of Allium cepa var. aggregatum root tips. Triphenyltetrazolium chloride and Evans Blue staining were used to observe mitochondrial and apoptotic activities. The results showed that at higher concentrations (250 ppm and 500 ppm), the encapsulated E. acoroides extract decreased mitotic indices; however, no chromosome aberration observed. NiNO3 itself induced a genotoxic effect as observed by low mitotic index and a high percentage of chromosome aberration. The modulation of NiNO3 effect by adding the encapsulated E. acoroides extract at low concentration (100 ppm) increased mitotic index compared to treatment with Ni alone, but did not reduce chromosome aberration. Simultaneous encapsulated E. acoroides extract and Ni treatment, significantly reduced nuclear fragmentation and nuclear lesion. The encapsulated E. acoroides extract can repair several types of nuclear damage but cannot minimise chromosomal damage.

Identification and characterization of Ethyl gallate from Ethyl acetate fraction of Phyllanthus emblica fruit, and invitro free radical scavenging activity

Phyllanthus emblica fruit has a rich source of polyphenolic compounds and is widely used due to its medicinal properties. A portion of the ethyl acetate fraction (EAF) from 70% methanol extract (70% ME) showed greater 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) scavenging activities. Moreover, EAF has more polyphenol content than 70% ME. The EAF was subjected to a dry silica gel column eluted successively with a mixture of chloroform: ethyl acetate: formic acid (2.8: 2.4: 0.4ml) as a mobile phase solvent system, and to afford various fractions. EAF and isolated fraction-1 of ethyl gallate (EG) showed a unique pattern of EG standard chromatogram in thin layer chromatography (TLC) analysis. EAF and isolated fraction-1 real time (R.T) of the peaks were unique compared with those of the standard chromatogram in high-performance liquid chromatography (HPLC) analysis. This chromatogram fraction was collected from isolated fraction-1 at the same R.T time by multiple HPLC analysis. The collected fraction from HPLC was injected into Mass spectroscopy (MS) and it showed a molecular ion at m/z 197 corresponding to C9H10O5. The substance was identified as EG based on the results mentioned above.

Potential Impacts of Prunus domestica Based Natural Gum on Physicochemical Properties of Polyaniline for Corrosion Inhibition of Mild and Stainless Steel.

The lack of an eco-friendly approach towards application of polyaniline as a coating material has been one of the most challenging tasks. Herein, the synthesis of green Prunus domestica gum grafted polyaniline (PDG-g-PANI) composite is reported by a cost-effective emulsion polymerization for application as an efficient anti-corrosion material for mild steel (MS) and stainless steel (SS) in a strong corroding environment. The composite formation was confirmed by Ultraviolet Visible (UV-Visible) and Fourier Transformed Infrared (FTIR) spectroscopies. X-ray diffraction data revealed the amorphous nature of the PDG-g-PANI. Scanning Electron Microscopic (SEM) images showed a bi-layered structure having a parent porous layer of PANI coated with afibrous layer of PDG. The solubility test confirmed the dissolution of PDG-g-PANI in common organic solvents such as acetone, ethanol, propanol, butanol, chloroform, N-Methyl-2-pyrrolidone, dimethyl sulfoxide, and the mixture of propanol and chloroform. The polarization curve, open circuit potential, electrochemical impendence spectroscopy (EIS), and gravimetric analysis were applied to investigate the corrosion protection behavior of the composite on MS and SS in 3.5% NaCl and 1 M H2SO4 solution. The PDG-g-PANI-coated MS exhibited 96% corrosion inhibition efficiency as compared to 86% and 43% for pristine PANI and PDG in 3.5% NaCl solution while PDG-g-PANI-coated SS showed 98% corrosion inhibition efficiency. Moreover, 99% and 96.6% corrosion protection was observed for PDG-g-PANI-coated MS and SS in 1 M H2SO4 solution. Gravimetric studies revealed that PDG-g-PANI coating can protect MS up to 93% for 14 days in salt solution while 97% corrosion inhibition efficiency was retained for 2 months in open air.

Cleavable epoxy networks using azomethine-bearing amine hardeners

This work is a proof-of-concept of the use of azomethine-bearing diamines as novel hardeners of standard epoxy compounds to yield cleavable and thermoformable covalent adaptable networks (CANs), with functional properties otherwise comparable to conventional epoxy networks. A suitable aromatic diamine (TPA-o-PD) was synthesised at acceptable purity for the intended use and successfully reacted with DGEBA. The resulting azomethine-bearing cured epoxy networks exhibited glass transition temperature values and a thermal stability profile similar to conventional epoxy network counterparts. In contrast to their conventional counterparts however, the azomethine-bearing networks were shown to dissolve in mixtures of chloroform and methanesulfonic acid, due to acid hydrolysis of at least some of the azomethine bonds of the network. The resulting recyclate material after evaporating the solvent was consistent with the profile of a thermoplastic polymer of high molecular weight, suggesting limited depolymerisation/network cleavage during dissolution in the chloroform/methanesulfonic acid mixture. The recyclates were soluble in polar aprotic solvents and showed good thermal stability, high Tg and molecular weight values, consistent with the attributes of engineering thermoplastics. Lastly, the cured networks were shown to be thermoformable at 200 °C, yielding self-standing films with only minor reduction of properties.

Sensitivity-Tunable Temperature SPR Sensor Based on Side-Opening Grapefruit Fiber With Liquid Mixture

We demonstrate a sensitivity-tunable temperature SPR sensor based on side-opening grapefruit fiber. The opening sections of the fiber are coated with gold layer and then filled with a liquid mixture of ethanol and chloroform as the sensing medium. The variation of the temperature will lead to different coupling efficiencies between the core-guided mode and the plasmonic mode, and then resulting in the change of loss spectra of the fiber that will be detected. Simulation results indicate that the temperature sensitivity of the sensor is 19.9 nm/°C at 10°C when the volume fraction of ethanol in the mixture is 0.1. Moreover, by adjusting the volume fraction, the sensitivity of proposed sensor can achieve the upper limit for a certain temperature range without the excitation of higher order plasmonic modes.

Comparative study of two versatile multi-analyte chromatographic methods for determination of diacerein together with four non-steroidal anti-inflammatory drugs: Greenness appraisal using Analytical Eco-Scale and AGREE metrics

According to green analytical chemistry (GAC) principles, multi-analyte methods are usually more preferred than methods determining one analyte at a time (principle 8) as they allow saving resources (time, reagents and money) (principle 9) and permit the reduction of generated waste (principle 7) as well as reduction of needed samples (principle 2). The present work herein, describes for the first time the development, validation and comparison of novel green versatile multi-analyte HPLC-DAD and HPTLC methods for the quantitative estimation of five drugs (diacerein, aceclofenac, diclofenac sodium, celecoxib and meloxicam) within a single run in a short analysis time. For HPLC-DAD, separation was performed through using Zorbax SB C18 (4.6 × 250 mm, 5 μm particle size) with the mobile phase composed of 0.05 M phosphate buffer pH 3.0 and acetonitrile (42:58, v/v) at a flow rate of 1 mL/min. The chromatograms were extracted at 258, 276 and 355 nm. In HPTLC procedure, precoated TLC silica gel aluminum plates 60 F254 were used with a mobile phase consisting of mixture of (chloroform: methanol: acetic acid, 92:8:0.25, v/v/v). The developed plates were scanned densitometrically at 258, 280 and 360 nm. Validation of the proposed methods was performed following the ICH guidelines for linearity, ranges, precision, accuracy, robustness, detection and quantification limits. Good linearities were confirmed by the high values of correlation coefficients (r > 0.9992). Appraisal of the greenness of the developed methods and comparison with different reported chromatographic methods was performed using the analytical Eco-scale (AES) approach and the novel Analytical GREEnness (AGREE) metric.

Simple, fast and reliable CE method for simultaneous determination of ciprofloxacin and ofloxacin in human urine

A simple, fast, and accurate capillary zone electrophoresis method has been developed for the determination of ciprofloxacin and ofloxacin. This method uses liquid–liquid extraction. Therefore, it is characterized by a very simple procedure of sample preparation but at the same time satisfactory precision and accuracy. The extraction process of the same urine sample was repeated three times. The extraction protocol was performed each time for 15 min with 1 mL of dichloromethane and chloroform mixture in a 3:1 volume ratio. A 0.1 mol/L phosphate-borate buffer (pH 8.40) was selected as the background electrolyte. UV detection was performed at 288 nm. The separation was carried out at a voltage of 16 kV, at a temperature of 25 °C. Experimentally evaluated LOQ values for ciprofloxacin and ofloxacin were 0.2 nmol/mL urine and 0.05 nmol/mL urine, respectively. For both analytes the calibration curves exhibited linearity over the entire tested concentration range of 1–6 nmol/mL urine. The precision of the method did not exceed 15%, and the recovery was in the range of 85–115%. The developed and validated procedure was applied to analyze human urine for the content of ciprofloxacin and ofloxacin.

High-Throughput Single-Step plasma sample extraction optimization strategies with experimental design for LC-MS and GC–MS integrated metabolomics and lipidomics analysis

To acquire deeper insights into the underlying molecular mechanisms in biological systems, a comprehensive and in-depth examination of a wide diversity of molecular species is necessary. Especially, it is very crucial to examine intermediary molecular levels such as protein, metabolite, and lipid to demonstrate direct causative and functional linkages between genotype and phenotype. Therefore, multiple sample sets/aliquots and analytical methods are required to cover different intermediary molecular levels due to the dissimilarity of physicochemical characteristics of biomolecules. However, existing methods used for simultaneous analysis of metabolites and lipids have not been thoroughly tested for reproducibility and wide applicability. Here, we have developed and optimized high-throughput and robust metabolomics and lipidomics analysis using experimental design strategies for single-step extraction protocols and also method parameters. Due to the high number of variables, an approach based on a desirability function was applied to optimize sample preparation and chromatographic parameters of metabolomics and lipidomics analysis. In these experiments, metabolite extraction efficiency was tested with acetone, acetonitrile, ethanol, methanol, water, and their combination, while lipids with hexane, chloroform, dichloromethane, and methyl tert-butyl ether. In the presented study, it is found that methanol:water:chloroform (3:1:3, v/v/v) mixture was superior to the other extraction solvent combinations in all performance measures. Moreover, the derivatization steps in GC–MS and chromatographic parameters in LC-qTOF-MS were tested. The derivatization efficiency increased with a higher concentration of methoxyamine hydrochloride and incubation time with the derivatization reagent. For LC-qTOF-MS, reconstitution solution, and the column temperature was found critical for high throughput metabolomics and lipidomics analysis, respectively. This systematic optimization for sample preparation and method parameters for integrated GC–MS and LC-qTOF-MS allows simultaneous and high-throughput analysis of metabolites as well as lipids from a single sample, making it a simple and practical strategy for different sample types.

A self-verification temperature sensor based on surface plasmon resonance in a hollow core negative curvature fiber

We proposed and simulated a surface plasmon resonance (SPR) temperature sensor with two loss peaks in a hollow core negative curvature fiber (HC-NCF). Inner walls of the anti-resonant tubes in HC-NCF were plated with gold films to stimulate SPR, while the thermo-optic mixture of toluene and chloroform was filled in the air holes in HC-NCF to modulate the coupling between core modes and surface plasmon polaron modes (SPPMs). Simulation results showed that two SPPMs with opposite thermo-optic respond effects were excited at two separate wavelength bands due to their different dispersion characteristics. Temperature measurement sensitivities of −3.976 nm °C−1 and 1.071 nm °C−1 were obtained for the two SPPMs, while the sensitivity reached −5.047 nm °C−1 when detected the wavelength interval between the two SPPMs loss peaks. The two separate loss peaks could also be utilized in self-verification. The designed temperature sensor based on HC-NCF and SPR depicts high sensitivity and self-verification, which could be utilized for high precision and stable temperature monitoring.

Production and Characterization of a Bioflocculant from Pichia kudriavzevii MH545928.1 and Its Application in Wastewater Treatment.

A variety of flocculants have been used to aggregate colloidal substances. However, recently, owing to the adverse effects and high costs of conventional flocculants, natural flocculants such as microbial flocculants are gaining attention. The aim of the study was to produce and characterize a bioflocculant from Pichia kudriavzevii MH545928.1 and apply it in wastewater treatment. A mixture of butanol and chloroform (5:2 v/v) was used to extract the bioflocculant. Phenol–sulphuric acid, Bradford and Carbazole assays were utilized for the identification of carbohydrates, proteins and uronic acid, respectively. Scanning electron microscopy (SEM) and elemental detector were employed to determine the surface morphology and elemental compositions. The removal efficiencies were 73%, 49% and 47% for BOD, COD and P, respectively. The bioflocculant (2.836 g/L) obtained showed the presence of carbohydrates (69%), protein (11%) and uronic acid (16%). The bioflocculant displayed a cumulus-like structure and the elemental composition of C (16.92%), N (1.03%), O (43:76%), Na (0.18%), Mg (0.40%), Al (0.80%), P (14.44%), S (1.48%), Cl (0.31%), K (0.34%) and Ca (20.35). It showed the removal efficiencies of 43% (COD), 64% (BOD), 73% (P) and 50% (N) in coal mine wastewater. This bioflocculant is potentially viable to be used in wastewater treatment.

Electrochemical behavior of polydiphenylamine-2-carboxylic acid and its hybrid nanocomposites with single-walled carbon nanotubes on anodized graphite foil in lithium aprotic electrolyte

Electrochemical properties of novel electrode coatings based on polydiphenylamine-2-carboxylic acid (PDPAC) and its hybrid nanocomposites with single-walled carbon nanotubes (SWCNT) were studied for the first time. PDPAC and SWCNT/PDPAC nanomaterials were synthesized via in situ oxidative polymerization in the homogeneous acidic medium (in 5 М H2SO4) and in the heterophase system in an alkaline medium (in a mixture of chloroform and NH4OH). Hybrid electrodes are flexible strips of anodized graphite foil (AGF) with electroactive layers of stable suspensions of polymers and nanocomposites in formic acid (FA) formed on their surface, without any binding and electrically conductive additives. The roughened surface and presence of oxygen-containing groups on the AGF surface provide good adhesion of the electroactive coatings. The use of the modified graphite foil as a current collector leads to a significant increase in the electrochemical capacitance and stability of the coatings. The specific electrochemical capacitance of electroactive coatings on AGF depends on the reaction medium pH for the coatings synthesis and reaches 421, 258, 150 F∙g−1 for PDPACac and 438, 350, 259 F∙g−1 for SWCNT/PDPACac, prepared in an acidic medium (pH = 0.3), and 202, 106, 63 F∙g−1 for PDPACalk and 278, 191, 129 F∙g−1 for SWCNT/PDPACalk, obtained in an alkaline medium (pH = 11.4), at charge-discharge currents of 0.5, 1.5, 3.0 mА·cm−2, respectively, in 1 М LiClO4 organic electrolyte in propylene carbonate. The PDPAC and SWCNT/PDPAC electroactive coatings are characterized by high stability of electrochemical properties at Coulombic efficiency up to 96–100%. The main contribution to the electrochemical capacitance is provided by the charging of the electric double layer.

Surfactant-free GO-PLA nanocomposite with honeycomb patterned surface for high power antagonistic bio-triboelectric nanogenerator

While triboelectric nanogenerators (TENGs) made of biomaterials are becoming significant components of self-charged monitoring healthcare systems, most of them show low output performance and poor durability. Herein, a surfactant-free graphene oxide-polylactic acid (GO/PLA) nanocomposite with customizable honeycomb patterns was, for the first time, prepared via a scalable two-step solution method to achieve a power-boosted biocompatible TENG. The first step of this method involved using a suitable solvent (such as dimethylformamide) to well disperse the GO nanoparticles into PLA. Subsequently, honeycomb patterns were induced by using a mixture of chloroform and methanol as a suitable volatile solvent/nonsolvent pair for improved phase separation. The results indicated that GO nanoparticles with large surface area and abundant electron-donating groups decorated the honeycomb patterns and significantly influenced the electro-positivity and surface properties of the PLA bio-polymer. An unprecedented antagonistic TENG ( A- TENG) based on the concave-honeycomb GO-PLA ( hc- GO/PLA) and its corresponding convex-polydimethylsiloxane ( c- PDMS) form a pair of tribo-components with antagonistic friction surfaces and generate an output power of 3.25 mW, which is 13.6 times higher than that of a flat-surface TENG ( f -TENG) without GO additives. We believe that the incorporation of functional GO nanoparticles without surfactants expands the potential applications of biocompatible A- TENG in healthcare areas thanks to its boosted output performance and persisting biocompatibility. • A new surfactant-free patterning technique for GO/PLA nanocomposite. • Pattern features are adjusted. • New design of antagonistic TENG for significantly boosting performance. • Bio A- TENG can power wearable electronics.

Simultaneous TLC-densitometric analysis of catechin, pyrocatechol and quercetine in gambir block from Pesisir Selatan

The goal of this study is to use the TLC-densitometric method to determine the concentration of catechin, pyrocatechol, and quercetine in gambir block extracts in a reliable and efficient manner. The best eluent is a mixture of chloroform: ethyl acetate: glacial acetic acid (4:4:2). The concentration of catechin, pyrocatechol and quercetine in gambir block was found to be 25.50 ± 3.13, 0.91 ± 0.60 and 0.83 ± 0.34% (w/w) w/w respectively. The linearity was obtained between 750-2500, 50–350, and 50–350 μg/spot. 12.49–41.63, 0.48–1.60, 3,85–12.83 μg/spots were found to represent the LOD and LOQ, respectively. The proposed approach exhibited great sensitivity, precision, and accuracy, as well as strong linearity.

Synthesis, crystal structure and supramolecular self-assembly of tetraphenylethylene subunit appended isoindigo derivatives

In this work, we design and synthesis donor-acceptor-donor based two new chromophores containing isoindigo (IN) as an acceptor core functionalised with two donor tetraphenylethylene (TPE) on the periphery one without thiophene spacer (Coded as: TPE-IN1) another derivative with thiophene as a spacer (Coded as: TPE-IN12. For the synthesis of both the derivatives Suzuki cross-coupling reaction was employed. Fluorescence emission spectral proeprties of TPE-IN1 and TPE-IN2 was investigated in mixture of chloroform (CHCl3):methylcyclohexane (MCH) and tetrahydrofuran (THF):water (H2O). The results shows an aggregation-caused quenching (ACQ) effect, which may be due to energy/electron transfer from TPE to IN core, as TPE is typically aggregation induced emission (AIE)-active chromophore. The self-assembled/aggregated structures in solution was characterized by means of fluorescence lifetime and dynamic light scattering (DLS) measurement. The crystalline morphology on the silicon wafer was investigated by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. Furthermore, our study of supramolecular self-assembly of TPE-IN1 and TPE-IN2 in THF:H2O (10:90%) and CHCl3:MCH (10:90%) solvent mixes shows various superstructures. Typically, TPE-IN1 displayed interesting hexagonal rod like morphology in THF:H2O mixture, where as TPE-IN2 showed self-assembled crystalline fibrous morphological micro and nanostructures via the solvophobic effect.

Thermodynamic properties of N-octyl pyridinium hexafluorophosphate ionic liquid: Characterization and application in separation of the azeotrope

The experimental data of the weight fraction activity coefficient (Ω12∞), the Flory–Huggins interaction parameter (χ12∞), the activity coefficient at infinite dilution (γ12∞) and the Hildebrand solubility parameters (δ2) involving N-octyl pyridinium hexafluorophosphate ([OPY][PF6]) ionic liquid (IL) have been evaluated by Inverse gas chromatography (IGC). The values indicated the interaction of solvents-IL depended on the structure of the solvents and the experimental temperatures. Based on IGC data, the isothermal vapor–liquid equilibrium (VLE) data of solvent-IL at 343.15 K were derived and related to the NRTL model. The acquired binary interaction parameters have a great significance in order to model. The equilibrium phase diagram of the [OPY][PF6]-acetone/chloroform–methanol ternary system was obtained by Aspen Plus simulation. The result showed that the IL can be used as a potential solvent for separating azeotropic mixtures of chloroform (1)/methanol (2) and acetone (1)/methanol (2).

Self-diffusion and molecular association in the binary systems dimethyl sulfoxide – chloroform and acetone – chloroform

The self-diffusion of components of such binary mixtures as dimethyl sulfoxide (DMSO) – chloroform and acetone – chloroform has been investigated by pulsed gradient spin-echo nuclear magnetic resonance (PGSE NMR) method and molecular dynamics (MD) simulation at ambient conditions. The self-diffusion coefficients obtained by the experimental and theoretical methods are well agreed with each other. Detailed analysis of structural characteristics (fraction of molecules with i hydrogen bonds, the average number of hydrogen bonds), as well as interaction energy in hydrogen-bonded complexes of DMSO – DMSO, DMSO – chloroform, acetone – acetone, acetone – chloroform made it possible to estimate the influence of the self- and heteroassociation on the self-diffusion of the mixture components. A set of methods showed that it is necessary to take into account not only heteroassociates with a composition of 1:1 just like acetone – chloroform mixture for sufficient approximation of the experimental data for DMSO – chloroform mixture. It has been established that for cosolvents (DMSO and acetone) with a similar molecular structure, a different behavior of concentration dependences of the self-diffusion coefficients in binary systems is connected with the features of self-association and heteroassociation.