Nature Of Organic Solvent Research Articles

Extraction and sorption preconcentration of rhenium with the use of 2-phosphorylphenoxyacetamides

Interfacial distribution of micro amount of ReO4 - between aqueous solutions of mineral acids and solutions of 2-phosphorylphenoxyacetamides in dichloroethane has been studied. Stoichiometry of extracted complexes has been determined; the effect of HNO3, HCl, and H2SO4 concentration in aqueous phase, extractant structure, and organic solvent nature on the efficiency of ReO4 - ions transfer into organic phase has been considered. It has been shown that Re(VII) can be selectively recovered and concentrated with complexing sorbent obtained by the noncovalent binding of 2-[2-(diphenylphosphoryl)-4-ethylphenoxy]-N,N-dioctylacetamide on the surface of macroporous polymer Amberlite XAD7HP.

Optimization of dye extraction from Cordyline fruticosa via response surface methodology to produce a natural sensitizer for dye-sensitized solar cells

In the present work, the application of response surface methodology (RSM) for the optimization of process parameters in the chlorophyll extraction from Cordyline fruticosa leaves was performed. The absorbance of the extract obtained from the extraction process under different conditions was estimated using the D-optimal design in RSM. Three different process parameters such as the nature of organic solvent based on their boiling point (ethanol, methanol, and acetonitrile), pH (4–8) and extraction temperature (50–90°C) were optimized for chlorophyll extraction. The effects of these parameters on the absorbance or concentration of the extract were evaluated using ANOVA results of quadratic polynomial regression. The results showed a high R2 and adjusted R2 correlation coefficients of 0.9963 and 0.9921 respectively. Moreover, the analysis of the final quadric model based on the design experiments indicated an optimal extraction condition of pH of 7.99, extraction temperature of 78.33°C, and a solvent boiling point, 78°C. The predicted absorbance was 1.006, which is in good agreement with the experimentally obtained result of 1.04 at 665nm wavelength. The application of pigment obtained under the optimal condition was further evaluated as a sensitizer for the dye sensitized solar cells. Maximum solar conversion efficiency (η) of 0.5% was achieved for the C. fruticosa leaf extract obtained under the optimum extraction conditions. Furthermore, the exposure of the leaf pigment to 100mW/cm2 simulated sunlight yielded a short circuit photocurrent density (Isc) of 1.3mA, open circuit voltage (Voc) of 616mV, and a fill factor (ff) of 60.16%.

Impact of heating mode in synthesis of monodisperse iron-oxide nanoparticles via oleate decomposition

The present work introduces the optimization of a synthetic procedure for oleate-coated iron-oxide nanoparticles by the thermal decomposition of Fe oleate dried at 30 and 70 °C in high-boiling organic solvents. The attention is focused on the temperature of the thermal decomposition, the nature of organic solvent, heating rate and the mode of the heating. In particular, heating on Wood alloy with simultaneous bubbling of argon through the reaction mixture versus the heating on mantel with magnetic stirring is highlighted as a route to improve the monodispersity of the nanoparticles. The effect of heating mode and rate on the nanoparticles size is estimated. The obtained tendencies point to the heating mode and rate as additional factors affecting the kinetic separation between nucleation and nanoparticle growth processes.

Preparation of Nano-curcumin with Enhanced Dissolution Using Ultrasonic-Assisted Supercritical Anti-solvent Technique

Abstract Curcumin is the main gradient of “Turmeric” a famous Indian spice and food additive. The marvelous nutritional and medicinal effects of curcumin made it a good alternative to some conventional drugs and food flavoring or coloring materials. However, the low solubility of curcumin is a challenging hindrance which should be seriously addressed. In this work, we prepared nano-curcumin with enhanced aqueous dispersion and dissolution rate. Ultrasonic-assisted supercritical anti-solvent (UA-SAS) technique was used to convert the commercial curcumin to uniform distributed nano-particles with the average size of 20 nm and yielding of 65%. The effect of process parameters including pressure, temperature, solution flow rate, and nature of organic solvent on the average particle size and yielding of products was investigated. The morphology, size, and crystalline pattern of processed curcumin particles were characterized by scanning electron microscopy, mean particle size analyzer, and X-ray diffraction. The champion specimen was achieved when the supercritical fluid was employed at 16 MPa and 35°C. Aqueous suspension of processed nano-curcumin can be stable for more than 2 months. In vitro dissolution experiments showed a remarkable enhancement in dissolution rate of UA-SAS-treated curcumin respecting to the commercial curcumin powder.

Determination of phenazopyridine in biological fluids using electromembrane extraction followed by high-performance liquid chromatography

Recently, electro-assisted extraction of ionic drugs from biological fluids through a supported liquid membrane and into an aqueous acceptor solution was introduced as a new sample preparation technique and has been termed electromembrane extraction (EME). In the present work, this microextraction technique combined with high-performance liquid chromatography and ultraviolet detection has been developed for detection of phenazopyridine (PP) as a local analgesic drug in human plasma and urine samples. From a 6.5 mL neutral aqueous sample, PP was extracted for 20 min through a thin supported liquid membrane of 2-nitrophenyl octyl ether sustained in the pores of the wall of a porous hollow fiber and into an aqueous acidic acceptor solution (25 μL, containing negative electrode) by application of a DC electrical potential. The effects of several factors, including the nature of organic solvent, HCl concentration in donor and acceptor solutions, stirring speed, extraction time, and applied voltage on the extraction efficiency of the drug, were investigated and optimized. Satisfactory linearity ranges with correlation coefficients higher than 0.996 in different extraction media, admissible limits of detection (0.5 and 1.0 ng mL−1 in urine and plasma samples, respectively) and good repeatability and reproducibility (intra- and inter-assay precisions ranged between 3.7%–6.8% and 8.8%–12.5%, respectively) were obtained. The optimized EME procedure was applied to determine the concentration of PP in various matrices, such as plasma and urine samples, and satisfactory results were obtained.

Challenging core-shell stationary phases with the separation of closely related anti-cancer compounds: performance studies and application to drug quantitation in cell cultures with multi-well plate clean-up

In the present paper, we compare the chromatographic behaviour of six different stationary phases (5μm fully porous and 2.6μm core-shell particles, featuring octadecyl-, pentafluorophenyl-propyl- and phenyl-hexyl- functionalizations) for the separation of camptothecin and a family of closely related analogues of the natural anti-cancer drug luotonin A under different experimental conditions (organic solvent nature and proportion, temperature and presence of modifiers). We found two differentiated behaviours for the phenyl-hexyl-functionalized supports depending on the temperature. The efficiency and kinetic performance of fully porous vs. core-shell particles was compared by means of van Deemter and kinetic plots, using an optimized conventional HPLC system. Columns packing core-shell particles afforded improved efficiencies, permeabilities, analysis times and consumption of solvents. Nevertheless, our optimized system was not able to release the full intrinsic efficiencies of these columns. The replacement of acetonitrile with methanol had a dramatic effect in the behaviour of the pentafluorophenyl-propyl stationary phase. The aggregate of these results led us to select the core-shell C-18 stationary phase along with a H2O:MeCN gradient for the rapid and sustainable quantitation of the anti-tumour agents in cell cultures. A simple and rapid clean-up step was optimized using 96-well deproteinization and delipidation plates. The validation of the proposed analytical method showed excellent figures of merit. The combination of this sample pre-treatment procedure with the separation on core-shell particles yielded a fast methodology able to process a large number of samples with minimal waste generation and environmental impact.

Extractive and sorption preconcentration of rhenium(VII) with the use of phosphoryl-containing podands

Interphase distribution of micro amounts of ReO 4 − between aqueous solutions of mineral acids and solutions of phosphoryl-containing mono-, di-, and tripodands, derived from 1-(methoxydiphenylphosphoryl)-2-diphenylphosphorylbenzene in dichloroethane was studied. The stoichiometry of extracted complexes was determined, the effect of HNO3, HCl, and H2SO4 concentration in aqueous phase and the nature of organic solvent on the efficiency of transition of ions into organic phase was considered. The growth of the number of phosphoryl groups in podand molecule enhances its extraction ability toward Re(VII). The possibility of selective recovery and preconcentration of Re(VII) with complexing sorbent obtained by noncovalent binding of phosphoryl-containing podand on the surface of macroporous polymer Amberlite XAD7HP was shown.

HOLLOW FIBER-BASED LIQUID PHASE MICROEXTRACTION COUPLED WITH HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY FOR EXTRACTION AND DETERMINATION OF VITAMIN D3 IN BIOLOGICAL FLUIDS

The reliability of hollow fiber-based on using two immiscible organic solvents in the lumen and wall pores of hollow fiber was evaluated for extraction and preconcentration of trace amount of vitamin D3, prior to determination by HPLC-UV. The analyte was extracted from a 8-mL sample solution, into a thin layer of an organic solvent (n-dodecane) impregnated in hollow fiber pores, and finally back-extracted into a µL volume of organic solvent (acetonitrile) located inside the lumen of the hollow fiber. The effects of several factors such as the nature of organic solvent, hollow fiber length, stirring speed, extraction time, ionic strength, sample volume, and extraction temperature on the enrichment factors (EFs) were investigated. Under optimized conditions, the enrichment factor of 130, limit of detection (LOD) of 0.9 ng mL−1 were obtained. The calibration curve was linear within the range of 3 to 1000 ng mL−1 with reasonable linearity (R2 = 0.999). The percentages of relative within-day and between-day standard deviations (RSD %) based on six replicated determinations were 5.4 and 6.1, respectively. Finally, the feasibility of the proposed method was successfully evaluated by extraction, and determination of the analyte in the biological fluids and satisfactory results were obtained.

Effects of Reaction Conditions on Microstructures and Properties of Polyaniline Nanofibers through Interfacial Polymerization

Polyaniline (PANI) nanofibers were fabricated through chemical oxidative polymerization at various organic solvent/water interfaces. The products were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). It is found that the morphologies, microstructures and properties of PANI nanofibers depend not only on the nature of organic solvents but also the adding way of aniline monomers and oxidant.

Extractive and sorption preconcentration of rhenium(VII) ions with the use of bis(diphenylphosphoryl)-substituted aza podand

Interfacial distribution of trace amounts of ReO4− ions between aqueous solutions of mineral acids and solutions of diphosphoryl-substituted aza podand [Ph2P(O)CH2CH2OCH2CH2]2NBu (I) in dichloroethane was studied. The stoichiometry of extracted complexes was determined, the influence of HClO4, HNO3, HCl, and H2SO4 concentration in aqueous phase and the nature of organic solvent on the efficiency of transition of ReO4− ions into organic phase was considered. Aza podand I shows larger extraction ability toward Re(VII) than monophosphorylated amines. The possibility of selective extraction and preconcentration of ReO4− ions by a complex-forming sorbent obtained by the noncovalent binding of compound I on the surface of carbon nanotubes was shown.

Separation of racemic flavonoids by high performance liquid chromatography using chiral mobile phase additive

To perform chiral separation of three flavonoid racemates, including dihydrodaidzein, equol and alpinetin, a simple and effective method was developed by using sulfobutyl ether-beta-cyclodextrin (SBE-beta-CD) as a mobile phase additive in HPLC system. The effects of different factors on the chiral separation were investigated, including cyclodextrin (CD) types (alpha-CD, gamma-CD, beta-CD, methyl beta-CD), CD concentration (5, 10, 20 mmol/L), pH value, nature of organic solvents (methanol, ethanol, acetonitrile) and phosphate buffer concentration. The analysis was carried out on a Kromasil 100-5C18 column (250 mm x 4.6 mm, 5 microm). The mobile phase consisted of acetonitrile and 10 mmol/L SBE-beta-CD aqueous solution( containing 20 mmol/L KH2PO4, at pH 4.0 adjusted with phosphoric acid) (20: 80, v/v). The flow rate was set at 1 mL/min, the column temperature was 25 degrees C, and the UV detections of dihydrodaidzein, equol and alpinetin were carried out at 276, 280 and 290 nm, respectively. The established method was able to separate the three racemates, and the resolutions of the enantiomers (dihydrodaidzein, equol and alpinetin) were 1.8, 1.9 and 1.4, respectively. This method might be applied to separate various types of flavanoid enantiomers in chemical structure.

Hollow fiber‐based liquid membrane microextraction combined with high‐performance liquid chromatography for extraction and determination of trimetazidine in human plasma

A hollow fiber-based liquid phase microextraction strategy combined with high-performance liquid chromatography was evaluated for the quantitative determination of trimetazidine in human plasma. Trimetazidine was extracted from a 2.1 mL basified plasma sample (donor phase) into the organic solvent (n-octanol) impregnated in the pores of a hollow fiber and then extracted into an acidic solution (acceptor phase) inside the lumen of the hollow fiber. The result showed that transport of drugs from alkaline sample solution into 0.5 m HCl occurred efficiently when 25 μL of 250 mm sodium 1-octanesulfonate was added into the donor phase. Several parameters influencing the efficiency of the method, such as the nature of organic solvent used to impregnate the membrane, compositions of donor phase and acceptor phase, type and concentration of carrier, extraction time, stirring rate and salt concentration, were investigated and optimized. Under the optimal conditions, the calibration curves were obtained in the range of 5-200 ng/mL with reasonable linearity (r > 0.9980). The method was successfully applied to determine the concentration of trimetazidine in human plasma.

Use of hollow fiber liquid phase microextraction and HPLC for extraction and determination of apigenin in human urine after consumption of Satureja sahendica Bornm.

The applicability of hollow fiber liquid phase microextraction (HF-LPME) was evaluated for extraction and preconcentration of apigenin prior to its determination by HPLC. Different parameters affecting the HF-LPME recovery such as nature of organic solvent, pH of donor and acceptor phases, extraction time, stirring speed, salt addition were optimized. Under optimum conditions (1-octanol as organic solvent, pH of the donor phase=3 and pH of acceptor phase=11.5, extraction time of 75min, stirring speed of 1000rpm) limit of detection (LOD) of 0.1ng/mL, linear range of 0.5–300ng/mL and correlation of determination (R2) of 0.9956 were obtained. The relative intra and inter-day standard deviations (RSD%) based on five replicate measurement were 3.5% and 10.7% respectively. Enrichment factor of 315 and recovery 85% were achieved. Finally, the applicability of the proposed method was evaluated by extraction and determination of apigenin in urine sample after consumption of Satureja sahendica Bornm. which is a native medicinal plant from Iran. Concentration of apigenin in urine sample was found to be 6.20ng/mL.

Determination of 8 Diuretics and Probenecid in Human Urine by Gas Chromatography-Mass Spectrometry: Confirmation Procedure

A fast and sensitive method for determination of 8 diuretics (acetazolamide, bendroflumethiazide, bumetanide, chlorthalidone, furosemide, hydrochlorothiazide, metolazone, triamterene) and masking agent (probenecid) in human urine using gas-chromatography with mass spectrometric detection is described. The extraction of the substances as function of the nature of organic solvent, mixing time and pH of aqueous phase was studied. The tandem mass spectrometry was used to increase selectivity of diuretics determination due to elimination of background interferences. Fragmentation reactions were studied for each compound and their collision energies were optimized to obtain the best selectivity. The results of method’s validation demonstrate its suitability in routine analysis for confirmation purposes.

Effect of organic solvent on morphology and mechanical properties of electrospun syndiotactic polypropylene nanofibers

We study the stress–strain behaviors of the electrospun sPP single nanofibers as well as nonwoven mats, which were electrospun from sPP solutions using two different solvents (decalin and cyclohexane) by electrospinning. The effects of organic solvents were explored on the morphologies and the mechanical properties of the corresponding electrospun sPP single nanofibers and nonwoven mats. It was found that the nature of organic solvents dramatically affected the surface morphologies, the circular and looping deposition of the electrospun sPP fibers, and the mechanical properties. The tensile strength of both electrospun sPP single nanofibers and nonwoven mats prepared from decalin-base solution was stronger than that of cyclohexane-base solution.

Determination of 4 phenols in water by three phase hollow fiber microextraction coupled with high performance liquid chromatography

A method was investigated for the determination of 4 phenols in water by three phase hollow fiber microextraction coupled with high performance liquid chromatography. Some factors affecting the extraction efficiency were optimized, such as the nature of organic solvent, the concentration of acceptor phase, the pH value of donor phase, extraction time, stirring rate and salt concentration. The optimized conditions were as follows: 1-octanol was used as the organic solvent, the concentration of NaOH solution as acceptor phase was 0.09 mol/L, the pH value of donor phase was 4, the extraction time was 40 min, the stirring rate was 600 r/min and the NaCI concentration was 100 g/L. Under the optimal conditions, the detection limits (S/N = 3) of phenol, 4-methylphenol, 2,4-dimethylphenol and 2-naphthol were 0.4, 0.4, 1.2 and 0.4 microg/L, and the enrichment factors were 111.6, 129.5, 71.0 and 175.6, respectively. The proposed method was applied for the determination of the 4 phenols in real environmental water samples and the spiked recoveries were in the range of 85.9%-119.0% at the spiked levels of 5 and 50 microg/L. The method is simple, rapid, accurate and suitable for the determination of phenols in water samples.

Trace Determination of Tamoxifen in Biological Fluids Using Hollow Fiber Liquid-Phase Microextraction Followed by High-Performance Liquid Chromatography-Ultraviolet Detection

The applicability of hollow fiber liquid-phase microextraction (HF-LPME) combined with high-performance liquid chromatography-ultraviolet detection (HPLC-UV) was evaluated for the extraction and determination of tamoxifen (TAM) in biological fluids including human urine and plasma. The drug was extracted from a 15 mL aqueous sample (source phase; SP) into an organic phase impregnated in the pores of the hollow fiber (membrane phase; MP) followed by the back-extraction into a second aqueous solution (receiving phase; RP) located in the lumen of the hollow fiber. The effects of several factors such as the nature of organic solvent, compositions of SP and RP solutions, extraction time, ionic strength and stirring rate on the extraction efficiency were examined and optimized. An enrichment factor of 360 along with substantial sample clean up was obtained under the optimized conditions. The calibration curve showed linearity in the range of 1 - 500 ng?mL–1 and the limit of detection was found to be 0.5 ng?mL–1 in aqueous medium. A reasonable relative recovery (≥89%) and satisfactory intra-assay (3.7% - 4.2%, n = 3) and inter-assay (7.5% - 7.8%, n = 3) precision illustrated good performance of the analytical procedure in spiked human urine and plasma samples.

Solvent-Induced Transformation of Myo-Inositol Crystal

The objective of this study is to investigate the effect of organic solvents on pseudopolymorph transformation kinetics for clarifying the transformation phenomenon. In our previous study, we observed anhydrate and dihydrate crystals of myo-inositol in water and/or an ethanol–water system and transformation phenomena. However, we could not determine the detailed transformation mechanism in organic solvents. Therefore, we attempted adding seed crystals to different alcohol solvents, which resulted in the transformation of seed crystals of a dihydrate into anhydrate crystals. The transformation kinetics increased with a decrease in the alkyl carbon number in the solvents and also with an increase in the ethanol mass fraction. During the transformation process, fine anhydrate crystals were observed on the surface of dihydrate crystals, and the dihydrate crystals were found to dissolve and gradually decrease in size. On the basis of these results, we propose that the hydrophilic nature of organic solvents is a significant factor determining the pseudopolymorph transformation kinetics of myo-inositol. The transformation phenomena proceeded easily upon the addition of dehydrate seed crystals, as if the solvent had the driving force for the crystallization of a stable polymorph. We classified this unique mechanism as a “solvent-induced transformation.”

Microextraction of mebendazole across supported liquid membrane forced by pH gradient and electrical field

In the present study, extraction of mebendazole across a supported-liquid membrane (SLM) was performed based on two different driving forces: (1) pH gradient over the SLM, and (2) electrical field sustained over the SLM. The extracted drug concentration was studied using reversed-phase HPLC–UV. At passive extraction conditions, mebendazole was extracted from alkaline samples (0.01 mmol L −1 NaOH) into 1-undecanol immobilized in the pores of a porous hollow fiber of polypropylene (SLM), and then transported into 25 μL of 100 mM HCl as the acceptor solution. Under electrokinetic migration conditions, mebendazole transported under applied voltage from acidic solutions (100 mmol L −1 HCl) through 2-nitrophenyl octyl ether (NPOE) immobilized in the pores of hollow fiber, into 25 μL of 100 mmol L −1 HCl as the acceptor solution. The effects of several factors including the nature of organic solvent, pH of donor and acceptor solutions, extraction time and stirring speed on the extraction efficiency of the drug were investigated and optimized. Under optimal conditions, preconcentration factors (PF) of 211 and 190 were obtained for the drug based on passive transport and electromembrane extraction (EME), respectively. Also, linear range of 0.5–1000 μg L −1 with estimation of coefficient higher than 0.994 was obtained for both of the proposed methods. The results showed that EME has higher speed in comparison with simple passive transport. The methods were successfully applied to extract mebendazole from plasma and urine samples and satisfactory results were obtained.

ChemInform Abstract: Preparation and Properties of Heteropoly Molybdovanadate(V) Complexes.

Tetrabutylammonium salts of the mixed heteropoly molybdovanadate(V) anions, [Hx−1V(VxMo12−x)O40]4− (x=1–3) were prepared from a Mo(VI)–V(V)–CH3CN system at room temperature. These mixed heteropoly anions were distinguished by their voltammetric behavior; the anions with x=1, 2, and 3 were electroreduced by one-, two-, and three-electrons due to the peripheral V atoms at a glassy carbon electrode. The spectroscopic properties were also reported. Their formation conditions were compared with those of 12-molybdovanadate (V), [VMo12O40]3−, especially regarding the concentrations of Mo(VI), V(V), acid, and organic solvents, the nature of organic solvents, and the ionic strength of the system. It should be emphasized that the 12-molybdovanadate(V) and mixed molybdovanadate(V) complexes are not formed in the absence of organic solvents.