Liquid-liquid Extraction System Based on Non-ionic Surfactant-salt-H_2O and Mechanism of Drug Extraction

The utilization of solid-liquid extraction system based on polymer-(NH4)2SO4 -H2O on separation of metal ions and bio-active substances has been summarized1. Cloud point extraction (CPE) benefits the environment and has been used in separation of metal chelates, biomacromolecules and in pretreatment of environmental samples2-4. In a 10 mL color comparison tube 20% PEG-1000 and 2.5 g (NH4)2SO4 were chosen as phase separation condition at pH 5.5. The average extraction efficiencies we…     

Study on PEG-（NH4）2SO4 Aqueous Two-Phase System and Distribution Behavior of Drugs

The distribution behavior of chlorpromazine hydrochloride (CPZ), procaine hydrochloride (PCN) and procaine amide hydrochloride (PCNA) in polyethylene glycol (PEG800 or PEG1500)-(NH4)2SO4 aqueous two-phase systems has been investigated. The result shows that the PEG-(NH4)2SO4 aqueous two-phase system has potential extraction capability in small molecular drug separation. In PEG800-(NH4)2SO4 system, the extraction efficiencies (E) of CPZ, PCN and PCNA amount to 92.8%, 74.5% and 74.4%, respectively, with the distribution coefficients (KD) being 25.7, 5.9 and 5.8, correspondingly. In PEG1500-(NH4)2SO4 system, the extraction efficiencies (E) of CPZ,PCN and PCNA are 93.7%, 71.3% and 63.2%, respectively, with distribution coefficients (KD) of 39.6, 6.6 and 5.0,correspondingly. Based on the study on ultraviolet and fluorescence spectra and also distribution behavior of the drugs in PEG-(NH4)2SO4 aqueous two-phase system, extraction mechanism was further proposed that both hydrogen bond and hydrophobic interaction are involved in extraction.     

Evaluation of vacuum microwave-assisted extraction technique for the extraction of antioxidants from plant samples

In the present work, vacuum microwave-assisted extraction (VMAE) was to perform microwave-assisted extraction in vacuum. Two well-known antioxidants, vitamin C from guava and green pepper, and vitamin E (α-tocopherol and γ-tocopherol) from soybean and tea leaves, which were easy to be oxidized, were chosen as representative target compounds for the evaluation of VMAE. The extraction yields of vitamin C, α-tocopherol and γ-tocopherol in VMAE and those in MAE performed in atmosphere (air-MAE) were compared and the effects of extraction time, extraction temperature and sample matrix were studied. Moreover, the effects of the oxygen and subpressure invacuo were also discussed via performed MAE in N₂ atmosphere (N₂-MAE). The extraction yields of vitamin C, α-tocopherol and γ-tocopherol in VMAE were higher than that in air-MAE, 35% increments of vitamin C from green pepper, 22% increments of α-tocopherol and 47% increments of γ-tocopherol from tea leaves were obtained, respectively. The comparable increased extraction yields of vitamin C, α-tocopherol and γ-tocopherol in N₂-MAE to that in air-MAE confirmed that oxygen in system was the crucial factor for the oxidation of vitamin C and vitamin E, VMAE was beneficial for the extraction of these oxygen-sensitive compounds. In addition, the subpressure invacuo in the VMAE system also showed positive affect on the extraction yields. On the basis of preventing oxidation and improving extraction efficiency of target compounds because of less oxygen and subpressure invacuo in the extraction system, VMAE has good potential for the extraction of oxygen-sensitive and thermosensitive compounds from plant samples.     

Bixin extraction from defatted annatto seeds

Bixin is the major carotenoid in the seed of the Annatto plant (Bixa orellana L.). The aim of this study was to obtain extracts containing bixin from seeds that had been partially defatted by supercritical fluid extraction. Pressurized liquid extraction (PLE) and low-pressure solvent extraction (LPSE) methods were used, and the effects of the solvent, temperature, pressure, solvent mass to feed mass (S/F) ratio and ultrasonication were evaluated for the global yield (X₀(%)) and the bixin yield (BY(%)). Extraction conditions producing high yields of bixin were established for both the PLE and LPSE methods. Analysis of variance was used to examine the influence of the individual extraction variables in LPSE and PLE. For LPSE; significant effects were found for solvent, temperature, and the interactions of temperature with solvent and temperature with S/F. Solvent was the only variable that significantly affected X₀(%) and BY(%), for PLE. While ultrasonication did not significantly affect X₀(%) or BY(%), scanning electron microscopy analysis revealed structural changes in the vegetal matrix following this treatment.     

The effect of 2-hydroxypropyl-β-cyclodextrin on the excited triplet state of promazine and chlorpromazine

Chlorpromazine hydrochloride (CPZ) is a widely used anti-psychotic drug that induces skin photosensitization and photoallergy response after systematic use or topical applications. The photoallergic mechanism is still unknown. However, it has been proposed that the triplet excited state (³CPZ*) could participate in the photodamaging effects. In this work, we report the photophysical properties of the triplet excited state of CPZ and its parent derivative promazine hydrochloride (PZ) in the presence of 2-hydroxypropyl-β-cyclodextrin (HPC). Absorption measurements indicate that PZ and CPZ form an inclusion complex with HPC through a 1:1 stoichiometry. The equilibrium constant at 25 °C is (2.55 ± 0.09) × 10³ M⁻¹ and (3.27 ± 0.07) × 10³ M⁻¹ for PZ and CPZ, respectively. The CPZ and PZ triplet excited state properties changed in the presence of HPC. The triplet lifetime increases with HPC concentration that is related to the amount of drug bound. In addition, the triplet intersystem crossing quantum yield was determined to be 0.45 and 0.17 for PZ and CPZ, respectively, when more than 95% of the drug molecules are bound to HPC. Altogether, these results suggest that the microenvironment plays a crucial role in the ³CPZ* and ³PZ* properties and thus it can modulate their photosensitizing effects.     

Functionalized superparamagnetic nanoparticles with a polymer containing β‐cyclodextrin for the extraction of sertraline hydrochloride in biological samples

In this study, a novel magnetic nanoadsorbent was synthesized by grafting β‐cyclodextrin onto the modified surface of Fe₃O₄ nanoparticles for the sorption and extraction of sertraline hydrochloride from human biological fluids. The extracted sertraline hydrochloride was measured by high‐performance liquid chromatography. The grafted nanosorbent was confirmed by Fourier transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, and elemental analysis. The kinetic sorption of sertraline hydrochloride by magnetic nanosorbent was 1 h. The best temperature for sorption of sertraline hydrochloride was at 25°C at an optimum pH of 5. The adsorbed sertraline hydrochloride can be desorbed by using methanol solution containing acetic acid (5%) and trifluoroacetic acid (1%).     

The effect of flame coal oxidation on the solid and soluble products of its extraction

Solid and soluble products of THF and CH₂Cl₂ extraction of flame coal oxidised by four different oxidising agents (peroxyacetic acid (PAA), 5% HNO₃, O₂/Na₂CO₃, air/125 °C) were studied by elemental analysis and FTIR. The extraction yield with THF was much higher than that with CH₂Cl₂ for all samples. The greatest changes in elemental composition were in the extracts from coal oxidised by nitric acid. The sulphur content was lowest in extracts from coal oxidised with 5% HNO₃ and PAA. FTIR confirmed that coal treatment with nitric acid incorporates nitrogen into the coal structure.     

Cloud-point extraction of nodularin-R from natural waters

A cloud-point extraction (CPE) technique for the determination of a cyanobacterial hepatotoxin, nodularin-R, in aqueous media using a cationic surfactant, tricaprylmethylammonium chloride (Aliquat-336), was developed. Cloud-point phase separation of Aliquat-336 at ambient temperature was induced by the addition of sodium sulfate. The Aliquat-336/Na₂SO₄ CPE system displayed large preconcentration factor, F_C, for nodularin-R. At the operational CPE conditions, F_C of 709.2 was achieved. Distribution constant, K_D, of the distribution of nodularin-R between the surfactant-rich and aqueous phases of the CPE system was estimated to be (4.94±0.8)×10³. Coupled to liquid chromatography with UV detection, the CPE method offered a detection limit of 330 pg ml⁻¹ (in freshwater)/1.3 ng ml⁻¹ (in seawater) and a repeatability of 6.4% (in freshwater) (n=7, P<0.05) for nodularin-R in a sample of 25 ml. The CPE is a rapid process and no cleanup step is required. Effects of pH, natural abundant anion (chloride) and dissolved organic matters (DOM, humic acid, HA) on the extraction efficiency were evaluated. A double CPE technique was developed to overcome interferences encountered in the analysis of environmental samples. Applicability of the new method to the determination of nodularin-R in real coastal marine water samples has also been demonstrated.     

A novel magnetic poly(aniline-naphthylamine)-based nanocomposite for micro solid phase extraction of rhodamine B

A novel Fe₃O₄–poly(aniline-naphthylamine)-based nanocomposite was synthesized by chemical oxidative polymerization process as a magnetic sorbent for micro solid phase extraction. The scanning electron microscopy images of the synthesized nanocomposite revealed that the copolymer posses a porous structure with diameters less than 50 nm. The extraction efficiency of this sorbent was examined by isolation of rhodamine B, a mutagenic and carcinogenic dye, from aquatic media in dispersion mode. Among different synthesized polymers, Fe₃O₄/poly(aniline-naphthylamine) nanocomposite showed a prominent efficiency. Parameters including the desorption solvent, amount of sorbent, desorption time, sample pH, ionic strength, extraction time and stirring rate were optimized. Under the optimum condition, a linear spiked calibration curve in the range of 0.35–5.00 μg L⁻¹ with R² = 0.9991 was obtained. The limits of detection (3S_b) and limits of quantification (10S_b) of the method were 0.10 μg L⁻¹ and 0.35 μg L⁻¹ (n = 3), respectively. The relative standard deviation for water sample with 0.5 μg L⁻¹ of RhB was 4.2% (n = 5) and the absolute recovery was 92%. The method was applied for the determination of rhodamine B in dishwashing foam, dishwashing liquid, shampoo, pencil, matches tips and eye shadows samples and the relative recovery percentage were in the range of 94–99%.     

Determination of erythromycins in fermentation broth using liquid phase extraction with back extraction combined with high performance liquid chromatography

Liquid phase extraction with back extraction (LPE-BE) combined with high performance liquid chromatography-diode array detection (HPLC-DAD) was applied for the extraction and determination of erythromycin A, B and C in fermentation broths. According to this procedure, the fermentation broth with the adjustment pH at a fixed value of 10 was first mixed with organic solvent (V_broth/V_org = 1.0). After shaking, the mixture was separated into two phases by microfuging at 13,000 rpm for 15 min. Then back extraction was performed into the acidic aqueous phase with pH 5.0 (V_org/V_aq = 1.0). After centrifugation at 3000, the two phases were separated and 50 μL of the acidic aqueous phase was injected into the HPLC. The effects of different variables such as the nature of extraction solvent and the pH of samples and buffer were investigated. At the most appropriate conditions, dynamic linear ranges of 0.5–8, 0.1–0.9 and 0.1–0.9 mg mL⁻¹ and limits of detection of 0.03, 0.003 and 0.002 mg mL⁻¹ were obtained for erythromycin A, B and C, respectively. Relative standard deviations (RSDs) of the proposed method were less than 9.5%. The mean recoveries were 99.5%. The proposed method is simple and sensitive with highly clean-up effect and it can be used for monitoring the progress of erythromycin fermentation.     

Use of packed-fiber solid-phase extraction for sample clean-up and preconcentration of vitamin B_(12) before determination

A rapid and simple preconcentration step applying packed-fiber solid-phase extraction columns has been investigated to vitamin B_(12).The extraction performance of the new method was investigated preliminarily on vitamin functional drink.The analysis used a reversed-phase C_(18) column,with a photo-diode array detector at 220 nm.The samples were preconcentrated with packed-fiber solid-phase extraction columns.Good linearity was observed in vitamin functional drink.The repeatability of extraction performa...     

Gas purge-microsyringe extraction: A rapid and exhaustive direct microextraction technique of polycyclic aromatic hydrocarbons from plants

Gas purge-microsyringe extraction (GP-MSE) is a rapid and exhaustive microextraction technique for volatile and semivolatile compounds. In this study, a theoretical system of GP-MSE was established by directly extracting and analyzing 16 kinds of polycyclic aromatic hydrocarbons (PAHs) from plant samples. On the basis of theoretical consideration, a full factorial experimental design was first used to evaluate the main effects and interactions of the experimental parameters affecting the extraction efficiency. Further experiments were carried out to determine the extraction kinetics and desorption temperature-dependent. The results indicated that three factors, namely desorption temperature (temperature of sample phase) T_d, extraction time t, and gas flow rate u, had a significantly positive effect on the extraction efficiency of GP-MSE for PAHs. Extraction processes of PAHs in plant samples followed by first-order kinetics (relative coefficient R² of simulation curves were 0.731–1.000, with an average of 0.958 and 4.06% relative standard deviation), and obviously depended on the desorption temperature. Furthermore, the effect of the matrix was determined from the difference in E_app,d. Finally, satisfactory recoveries of 16 PAHs were obtained using optimal parameters. The study demonstrated that GP-MSE could provide a rapid and exhaustive means of direct extraction of PAHs from plant samples. The extraction kinetics were similar that of the inverse process of the desorption kinetics of the sample phase.     

Evaluation of Soxhlet extraction, accelerated solvent extraction and microwave-assisted extraction for the determination of polychlorinated biphenyls and polybrominated diphenyl ethers in soil and fish samples

Three commonly applied extraction techniques for persistent organic chemicals, Soxhlet extraction (SE), accelerated solvent extraction (ASE) and microwave-assisted extraction (MAE), were applied on soil and fish samples in order to evaluate their performances. For both PCBs and PBDEs, the two more recent developed techniques (ASE and MAE) were in general capable of producing comparable extraction results as the classical SE, and even higher extraction recoveries were obtained for some PCB congeners with large octanol-water partitioning coefficients (K_ow). This relatively uniform extraction results from ASE and MAE indicated that elevated temperature and pressure are favorable to the efficient extraction of PCBs from the solid matrices. For PBDEs, difference between the results from MAE and ASE (or SE) suggests that the MAE extraction condition needs to be carefully optimized according to the characteristics of the matrix and analyte to avoid degradation of higher brominated BDE congeners and improve the extraction yields.     

Flow-injection on-line oxidizing fluorimetry and solid phase extraction for determination of thioridazine hydrochloride in human plasma

A simple, sensitive and specific fluorimetric method has been developed for the determination of thioridazine hydrochloride in human plasma involving solid phase extraction (SPE). In a flow-injection system, thioridazine hydrochloride is on-line oxidized into a strongly fluorescent compound with a lead dioxide solid-phase reactor and the fluorescence intensity is measured with a fluorescence detector (λ_ex = 349 nm, λ_em = 429 nm). A comparison of plasma sample pretreatment between SPE procedure and precipitation method was made and the results showed that SPE procedure was better than precipitation method. Under the optimum conditions, the fluorescence intensity is proportional to the concentration of thioridazine hydrochloride in the range from 0.015 to 2.000 μg mL⁻¹. The detection limit is 5.5 ng mL⁻¹ of thioridazine hydrochloride and the relative standard deviation is 1.06%. This method has been applied to determination of thioridazine hydrochloride in real patients plasma samples with the results compared with those obtained by HPLC method.     

Liquid-liquid extraction and recovery of indium using Cyanex 923

The extraction of In(III) from HCl, H₂SO₄, and HNO₃ media using a 0.20 mol l⁻¹ Cyanex 923 solution in toluene is investigated. In(III) is quantitatively extracted over a fairly wide range of HCl molarity while from H₂SO₄ and HNO₃ media the extraction is quantitative at low acid concentration. The extracted metal ion has been recovered by stripping with 1.0 mol l⁻¹ H₂SO₄. The stoichiometry of the In(III): Cyanex 923 complex is observed to be 1:2. The extraction of In(III) is insignificantly changed in diluents namely toluene, n-hexane, kerosene (160-200 °C), cyclohexane, and xylene having more or less the same dielectric constants, whereas, it decreases with increasing polarity of diluents such as cyclohexanone and chloroform. The extractant is stable towards prolonged acid contact and there is a negligible loss in its extraction efficiency even after recycling for 20 times. The extraction behavior of some commonly associated metal ions namely V(IV), Ti(IV), Al(III), Cr(III), Fe(III), Ga(III), Sb(III), Tl(III), Mn(II), Fe(II), Cu(II), Zn(II), Cd(II), Pb(II), and Tl(I) has also been investigated. Based on the partition data the conditions have been identified for attaining some binary separations of In(III). These conditions are extended for the recovery of pure indium from zinc blend, zinc plating mud, and galena. The recovery of the metal ions is around 95% with purity approximately 99%.     

Determination of sulfadimethoxine in milk with aptamer‐functionalized Fe3O4/graphene oxide as magnetic solid‐phase extraction adsorbent prior to HPLC

An aptamer (Apt) functionalized magnetic material was prepared by covalently link Apt to Fe₃O₄/graphene oxide (Fe₃O₄/GO) composite by 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide hydrochloride and N‐hydroxysuccinimide, and then characterized by FTIR spectroscopy, X‐ray diffraction, and vibration sample magnetometry. The obtained composite of Fe₃O₄/GO/Apt was employed as magnetic solid‐phase extraction adsorbent for the selective preconcentration of sulfadimethoxine prior to analysis by high‐performance liquid chromatography. Under the optimal conditions (sample pH of 4.0, sorbent dosage of 20 mg, extraction time of 3 h, and methanol‐5% acetic acid solution as eluent), a good linear relationship was obtained between the peak area and concentration of sulfadimethoxine in the range of 5.0 to 1500.0 µg/L with correlation coefficient of 0.9997. The limit of detection (S/N = 3) was 3.3 µg/L. The developed method was successfully applied to the analysis of sulfadimethoxine in milk with recoveries in the range of 75.9‐92.3% and relative standard deviations less than 8.1%. The adsorption mechanism of Fe₃O₄/GO/Apt toward sulfadimethoxine was studied through the adsorption kinetics and adsorption isotherms, and the results show that the adsorption process fits well with the pseudo‐second‐order kinetic model and the adsorbate on Fe₃O₄/GO/Apt is multilayer and heterogeneous.     

Synergistic extraction of lanthanum(III) from chloride medium by mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazalone-5 and triisobutylphosphine sulphide

The synergistic effect of 1-phenyl-3-methyl-4-benzoyl-pyrazalone-5 (HPMBP) and triisobutylphosphine sulphide (TIBPS, B) is investigated in the extraction of lanthanum(III) from chloride solution. Lanthanum(III) is extracted by the mixture as LaCl₂·PMBP·B_0.5 instead of La(PMBP)₃·(HPMBP) which is extracted by HPMBP alone. The equilibrium constants and thermodynamic functions such as ΔG, ΔH and ΔS are determined. The extraction of other rare earth ions by mixtures of HPMBP and TIBPS is also studied and the possibility of separating rare earth ions is discussed.     

Thermodynamics of solvent extraction of thallium with diethylhexyl phosphoric acid

The equilibrium molalities Tl⁺ were measured in {Tl₂SO₄ + Na₂SO₄ + D₂EHPA + n-C₈H₁₈ + Water} system at ionic strength from 0.1 to 2.0 mol kg^?1 containing Na₂SO₄ as supporting electrolyte in aqueous phase and at constant molality extractant at temperatures from 278.15 K to 303.15 K in organic phase. The standard extraction constants K ⁰ at various temperatures were obtained by methods of extrapolation and polynomial approximation. Thermodynamic quantities for the extraction process were calculated.     

Electrochemical assessment of water|ionic liquid biphasic systems towards cesium extraction from nuclear waste

A room temperature ionic liquid (IL) composed of a quaternary alkylphosphonium (trihexyltetradecylphosphonium, P₆₆₆₁₄⁺) and tetrakis(pentafluorophenyl)borate anion (TB⁻) was employed within a water|P₆₆₆₁₄TB (w|P₆₆₆₁₄TB or w|IL) biphasic system to evaluate cesium ion extraction in comparison to that with a traditional water|organic solvent (w|o) combination. ¹³⁷Cs is a major contributor to the radioactivity of spent nuclear fuel as it leaves the reactor, and its extraction efficiency is therefore of considerable importance. The extraction was facilitated by the ligand octyl(phenyl)-N,N′-diisobutylcarbamoylphosphine oxide (CMPO) used in TRans-Uranium EXtraction processes and investigated through well established liquid|liquid electrochemistry. This study gave access to the metal ion to ligand (1:n) stoichiometry and overall complexation constant, β, of the interfacial complexation reaction which were determined to be 1:3 and 1.6 × 10¹¹ at the w|P₆₆₆₁₄TB interface while the study at w|o elicited an n equal to 1 with β equal to 86.5. Through a straightforward relationship, these complexation constant values were converted to distribution coefficients, δ_α, with the ligand concentrations studied for comparison to other studies present in the literature; the w|o and w|IL systems gave δ_α of 2 and 8.2 × 10⁷, respectively, indicating a higher overall extraction efficiency for the latter. For the w|o system, the metal ion-ligand stoichiometries were confirmed through isotopic distribution analysis of mass spectra obtained by the direct injection of an emulsified water–organic solvent mixture into an electron spray ionization mass spectrometer.     

Preparation of carbon coated Fe3O4 nanoparticles and their application for solid-phase extraction of polycyclic aromatic hydrocarbons from environmental water samples

The carbon coated Fe₃O₄ nanoparticles (Fe₃O₄/C) were synthesized by a simple hydrothermal reaction and applied as solid-phase extraction (SPE) sorbents to extract trace polycyclic aromatic hydrocarbons (PAHs) from environmental water samples. The Fe₃O₄/C sorbents possess high adsorption capacity and extraction efficiency due to strong adsorption ability of carbon materials and large surface area of nanoparticles, and only 50 mg of sorbents are required to extract PAHs from 1000 mL water samples. The adsorption attains equilibrium rapidly and analytes are eluted with acetonitrile readily. Salinity and solution pH have no obvious effect on the recoveries of PAHs, which avoids fussy adjustment to water sample before extraction. Under optimized conditions, the detection limits of PAHs are in the range of 0.2–0.6 ng L⁻¹. The accuracy of the method was evaluated by the recoveries of spiked samples. Good recoveries (76–110%) with low relative standard deviations from 0.8% to 9.7% are achieved. This new SPE method provides several advantages, such as high extraction efficiency, high breakthrough volumes, convenient extraction procedure, and short analysis times. To our knowledge, this is the first time that Fe₃O₄/C nanoparticles are used for the pretreatment of environmental water samples.