Optimal Separation Conditions Research Articles

A rapid optimization method for Sepbox system separation using HPTLC: an application of Cerbera manghas L. separation.

The rapid isolation of natural products and efficient drug screening are pivotal in expediting drug development. Techniques ranging from traditional open column chromatography to medium-pressure liquid chromatography (MPLC), and the latest Sepbox technology, have been developed to accelerate separation processes and streamline drug development timelines. The Sepbox system combines two-dimensional high-performance liquid chromatography (2D-HPLC) and solid-phase extraction (SPE) technologies, coupled with UV and evaporative light scattering detection (ELSD) systems, offering various column options to cater to diverse sample requirements. Furthermore, the Sepbox system automates and expedites sample fractionation into numerous fractions, facilitating subsequent high-throughput screening and analysis. Despite previous emphasis on 2D-HPLC development, optimizing separation conditions with the Sepbox system poses challenges due to the requirement for substantial sample and solvent quantities, limiting its practicality compared to conventional methods. Hence, this study employed eight standard compounds to explore the correlation between retention factor (Rf) values obtained from high-performance thin-layer chromatography (HPTLC) plates and retention times on the Sepbox main column. Mass spectrometry was utilized to confirm the retention times of the standard compounds. The findings yielded a conversion equation between HPTLC Rf values and Sepbox main column retention times, thereby enhancing the separation efficiency of Sepbox 2D-2000 system. Finally, the efficacy of this method was validated using Cerbera manghas leaf crude extracts and its purified compounds, demonstrating the rapid optimization of suitable elution conditions for the Sepbox 2D-2000 system using HPTLC.

UPGRADING AND SURFACE COATING OF EGYPTIAN WHITE SAND WITH POLYMERS AND SILANES

Egypt is endowed with huge reserves of filler minerals, such as silica sand which form approximately 95% of the Earth's crust. The silica sand industry is used in many fields, such as pharmaceutical practices, chemicals, glass, ceramics, electronics, and photovoltaic industries. The aim of this study is to remove impurities from silica sand and apply surface modification processes to enhance its value for various industrial manufacturing applications. Various processing techniques, including classification, attrition scrubbing, magnetic separation, ultra-fine grinding and surface modification, were conducted throughout the study. The results indicated that attrition scrubbing to the classified size fraction of -0.6 + 0.1 mm was capable of reducing the iron concentration from 0.068% to 0.045%. Utilizing the Box-Behnken design, the optimal conditions for magnetic separation were identified, resulting in a decrease in iron content down to 0.012%. Simultaneously, the silica content increased from 99.05% to 99.76%. The results of ultrafine grinding using an attritor mill revealed that a grinding time of 2 hours is sufficient to reach a size suitable for the coating process. Surface modification of the produced ultrafine sand was conducted using polymers and silanes. The treated sand was characterized using SEM, zeta potential, adsorption density, and FTIR measurements. Notably, hydrophobicity increased, accompanied by an increase in particle size. Simultaneously, the surface becomes flatter, indicating the formation of a thin layer. Consequently, the coated sand proved to be a satisfactory material that met the criteria to be used as a filler in coating and paints.

Synthesis, Characterization and HPLC Analysis of Streptomycin with its Derivatives

A new streptomycin derivative was synthesized and identified using UV-Vis, FTIR, and HNMR; the streptomycin first derivative has a moderate inhibition \textit{Escherichia coli} compared to the standard medication, which did not give any inhibition to this type of bacteria. A sensitive, accurate RP-HPLC method was developed to separate these streptomycin derivatives from the standard streptomycin drug and applied for the drug analysis in pharmaceuticals at optimal separation conditions using the Nucludar C18-DB column. The results showed good separation between the standard streptomycin drug and its prepared derivatives; the first, second, and third derivatives have of 2.102, 6.19, and 7.695 min, respectively, while the standard streptomycin appeared at of 5.352 min. This method was applied for the separation and estimation of streptomycin in ABBOTT and TROGE pharmaceuticals via standard graph, and the results proved that this method is accurate and the obtained concentration values match what was proven by the drug manufacturer.

Using the thiomolybdate-loaded D201 resin derived from the W and Mo separation process as the scavenger of Cr(VI), Cu(II), and Pb(II)

Heavy metals (HMs) are recalcitrant and persistent in the environment, posing long-term detrimental effects to ecosystems and public health. Adsorption is an available method to sequester HMs from environmental media. Expensive tetrathiomolybdate (MoS42-) salts have been widely used to modify materials, showing favorable performance in removing HMs. Instead of using such a costly reagent, applying the W and Mo separation process to load thiomolybdate (MoOxS4-x2-) on a strong basic resin D201 as the scavenger of Cr(VI), Cu(II), and Pb(II) was proposed in this study. Assisted by the orthogonal experiment, the optimal separation conditions, i.e., pH = 7, ns/nMo = 8, [Mo]0 = 2 g/L, and solid/liquid ratio of 30, with desirable removal rates for Cr(VI) and Cu(II) were achieved. Compared with the control group (MoS42--loaded D021, MSD201), the resin (WMD201) collected from the optimized W and Mo separation conditions showed a comparable capacity and similar mechanism for the adsorption of the three HMs. The adsorption kinetics and isotherm results of metals on WMD201 were well fitted by the pseudo-second order and Langmuir modes, respectively. Increasing the initial pH from 1 to 4 resulted in a significant rise for the uptake of Cr(VI) and Pb(II). Different from Cu(II) and Pb(II), which were sequestered mainly by forming complexes with MoOxS4-x2- and/or S2-, the removal of Cr(VI) was partially attributed to ion exchange and reduction. These results suggest that using W and Mo separation processes to functionalize materials as the efficient scavengers of HMs is feasible.

A Facile and Effective Method to Strip and Recycle Spent LiFePO4 Cathode Materials

AbstractA facile and highly efficient method was proposed for the separation and regeneration of LiFePO4 (LFP) cathode materials from spent lithium‐ion batteries (LIBs). The optimal separation conditions involved immersing the spent LFP materials in NaOH (0.5 mol/L) solutions at a temperature of 90 °C, with a solid‐liquid ratio of 30 g/L under stirring of 500 rpm. The high separation effect can be attributed to the synergistic action of several factors at the interface. Furthermore, the structure, composition, morphology, and electrochemical performance of the regenerated LFP (D‐LFP) materials at different temperatures were systematically investigated. Notably, the D‐LFP material generated through calcination at 650 °C for 10 h exhibited a initial discharge capacity of 154.4 mAh g−1 at 0.5 C and the capacity retention rate of 97.3 % after 100 cycles. Moreover, a detailed investigation of the kinetics of the separation and regeneration processes was carried out, along with an exploration of the underlying electrochemical mechanism. This idea not only mitigates the harmful impact of waste on both human health and the environment but also realizes the transformation of waste into valuable resource treasure, promoting a greener and more sustainable development of society.

Gallium and germanium static and kinetic sorption and desorption studies on cerium dioxide nanoparticles

Positron-emitting 68Ga has become an integral part of nuclear medicine. It is a radionuclide obtained from 68Ge/68Ga radionuclide generators. Apart from other qualities, it is a feature that have caused its growing popularity in medical practice. Nevertheless, the increasing demand for 68Ga supply results in the need of new and improved separation systems to obtain it. Hydrous oxides such as titanium or zirconium dioxide are usually the preferred separation materials, but other oxidic materials are under study. Thorough testing of the sorption behaviour is often overlooked in these studies, though it is indispensable for the applicability and suitability assessment. This work is focused on the sorption behaviour description of cerium dioxide prepared by calcination of ceric nitrate. Both batch and kinetic sorption experiments were conducted. Such a thorough study has never been carried out for this material. In batch experiments, the optimal conditions for separation of 68Ga and 68Ge were found. Kinetic experimental data were used for mathematical modelling. Six kinetic models derived from various rate-controlling processes were used and their applicability was demonstrated. The diffusion in an inert layer is the rate-controlling process of both gallium and germanium sorption and desorption. This model description of sorption kinetics will further enable us to optimise the sorption and desorption processes numerically. Thus far, it was found out that the prepared cerium dioxide can quantitatively adsorb germanium in very short time of 10 min from 1mM hydrochloric acid and the most convenient medium for 68Ge and 68Ga separation is 0.1 M hydrochloric acid.

Enrichment and separation of recombinant adeno-associated virus particles by aqueous two-phase extraction

The adeno-associated virus (AAV) has been widely employed as a popular gene therapy vector. However, current methods for its separation and purification exhibit numerous limitations. In this study, polyethylene glycol (PEG)/salt aqueous two-phase system (ATPS) was utilized as an efficient and environmentally-benign approach to separate AAV. The separation efficiency of AAV particles from other cellular components was investigated using various ATPS compositions. The effects of PEG molecular weight, types of phase-forming salts, and concentrations of different components were tested and compared. The optimal separation conditions were determined to be 17 % (w/w) PEG 600, 16 % (w/w) sodium citrate, and 15 % (w/w) crude cell lysate. The AAV particles were predominantly enriched in the interphase, while the impurities were observed in the top and bottom phases. High AAV recovery (>99 %) and efficient impurity removal (>95 %) were achieved. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transmission electron microscopy were used to characterize and verify the separated AAV particles. The results indicated that aqueous two-phase extraction possesses a robust capability for the enrichment and separation of AAV particles directly from crude cell lysates, and it shows promising potential for the separation of other viral particles.

Flotation separation of scheelite from fluorite by new depressant nitrilotriacetic acid and its mechanism

BackgroundFluorite and scheelite are main resources for fluorine and tungsten respectively, which are usually associated with each other, and the separation of them has important strategic meaning. For the first time, scheelite and fluorite were separated by using nitrilotriacetic acid (NTA) as depressant. MethodsThe effects of NTA on the flotation of scheelite and fluorite were investigated by flotation experiments. The selective adsorption mechanism of NTA on fluorite were revealed by atomic force microscope (AFM), zeta potential measurements, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). Significant findingsNTA could achieve the efficient separation of scheelite from fluorite. Under the optimal separation conditions, the recovery of scheelite concentrate is 73.59 % and the grade of CaWO4 is 73.19 %, and the recovery and CaF2 grade of fluorite in tailings was 74.71 % and 79.44 % respectively. Mechanism study showed that although NTA had carboxy groups, NTA could not be adsorbed on scheelite surface due to the electrostatic repulsion and steric effect. However, NTA was strongly chemisorbed by calcium on fluorite, covering calcium groups and hiding the further adsorption of NaOL. Thus, NTA selectively disturbed NaOL adsorption and decreased the floatability of fluorite and realized the scheelite-fluorite separation.

Preparation of porous organic cage and its use as chiral stationary phase for capillary electrochromatography

Porous organic cages (POCs) are a unique type of microporous materials composed of discrete molecules with internal cavities that are accessible to various compounds. In this study, a prismatic chiral POC with good thermochemical stability was synthesized by condensing (1R,2R)-diaminocyclohexane and 3,3',5,5'-teturonic-4,4'-biphenediol via the Schiff base reaction and characterized by proton nuclear magnetic resonance spectroscopy, infrared (IR) spectroscopy, thermogravimetric analysis (TGA), and scanning electron microscopy. The IR spectrum of the POC revealed a strong characteristic absorption peak at 1635 cm-1, indicating that it formed imine bonds (C=N). The absorption peak at 3425 cm-1 was attributed to the stretching vibrations of -OH, the absorption peaks at 2925 and 2858 cm-1 were attributed to the stretching vibrations of N=C-H and C-H, and the absorption peaks at 1446 and 1383 cm-1 were attributed to the stretching vibrations of C=C-H and C=C in the benzene ring. High-resolution mass spectral analysis of the POC showed a molecular ion peak at m/z 1363.7228, indicating its successful synthesis. TGA was performed from 25 to 800 ℃ at a rate of 10 ℃/min, and the results of this analysis showed that the POC was stable up to approximately 300 ℃. The POC was dissolved in dichloromethane and uniformly coated on the inner wall of a quartz capillary via the dynamic coating method to prepare a capillary electrochromatographic column. The experimental results revealed that the chiral electrochromatographic column could not only resolve ofloxacin, Troger's base, 2-amino-1-butanol, and 1-phenyl-1-amyl alcohol but also separate the isomers of o-, m-, and p-toluidine and o-, m-, and p-chloroaniline, indicating its good chiral separation ability. Investigation of the optimal separation conditions for ofloxacin, Troger's base, 2-amino-1-butanol, and 1-phenyl-1-amyl alcohol revealed that the voltage, buffer solution concentration, and pH significantly affected their separation degree. In particular, the optimal separation voltage for ofloxacin, Troger's base, and 2-amino-1-butanol was 15 kV, while that for 1-phenyl-1-amyl alcohol was 17 kV. The optimal buffer concentration and pH for ofloxacin, Troger's base, 2-amino-1-butanol, and 1-phenyl-1-amyl alcohol were 0.100 mol/L and 7.5. Under optimal chromatographic conditions, the resolution values for ofloxacin, Troger's base, 2-amino-1-butanol, and 1-phenyl-1-pentanol were 1.80, 3.33, 1.69, and 1.18, respectively. The results collectively demonstrate that the prepared POC may serve as a good chiral stationary phase for capillary electrochromatography with a certain chiral resolution ability and has good application prospects in chromatographic separation.

B-186 Investigating LC Column Selectivity for 19 Steroids in a Clinical Research Setting

Abstract Background Steroids are a class of structurally related endogenous compounds. Several have the same chemical formula (and hence the same m/z) and must be chromatographically separated for accurate identification and quantitation by LC-MS/MS. Here, six bonded silica solid core or “core-shell” LC columns (see Table 1) were evaluated to determine selectivity and optimum separation conditions for a 19 analyte steroid panel for clinical research. The optimum column for the separation of estrone and estradiol was also established. Methods Analytical reference standards (Cerilliant®, Round Rock, TX) were used to prepare diluted samples for injection. Six different core-shell 2.6 µm, 50 × 2.1 mm LC columns (Kinetex™, Phenomenex, Torrance, CA) were evaluated (see Table 1). Detection employed a 7500 triple quadrupole LC-MS/MS equipped with an ESI source used in positive and negative mode (SCIEX®, Framingham, MA) coupled to an Agilent® 1290 liquid chromatograph (Agilent Technologies, Santa Clara, CA). Results The traditional C18 column worked best for the complete steroid clinical research panel. Estrogens had the best separation on the biphenyl phase, which demonstrated the highest level of selectivity for estrone and estradiol. The phenyl-hexyl column did not sufficiently separate all steroid isomers in the clinical research panel, however it was sufficient to separate estrone and estradiol. Conclusion The proposed HPLC conditions and the core-shell 2.6 μm 50 × 2.1 mm C18 column provided the best separation for 19 steroids with a fast 8 minute run time. For research focused on estrogens, the core-shell biphenyl column yielded the best separation.

Ultrasonic-assisted supercritical fluid separation removing plasticizers from ganoderma lucidum spores’ oil

Ultrasonic-assisted supercritical fluid separation (USFS) was firstly applied to regulate solubility and remove plasticizers from ganoderma lucidum spores’ oil to improve product safety. Separation efficiency was related with four variables, including temperature, pressure and ultrasonic power. The QD-T6A ultrasonic generator probe, which provided for the study with adjustable ultrasonic power 0 W to 800 W and the ultrasonic frequency was 40 kHz, was fixed at the entrance of the primary separation kettle. The optimal separation conditions were determined to be temperature as 15.0 °C, pressure as 18.0 MPa, and ultrasonic power as 360 W of ultrasonic power on the basis of response surface methodology (RSM). Experimental Di-n-butylphthalate (DBP) and Diethyl phthalate (DEP) content were 0.09 mg and 0.04 mg, respectively, which were below the limits for plasticizers. Meanwhile, the total triterpene and ganoderic acid A contents were 6.89 g and 1.10 g, respectively, comparable to conventional supercritical fluid extraction. The experiments with USFS at different power intensities revealed that ultrasonic at a power intensity of 36 W/L and the power density of 0.20 W/cm2 could resolve the separation contradiction between ganoderma lucidum spores’ oil and plasticizers. This study revealed that USFS could be an innovation in the field of ultrasonic separation, with numerous potentials uses in pharmaceutical manufacturing.

On-line preconcentration of fluorescein derivatives of essential amino acids using sweeping in a nonionic micellar system

A rapid and effective method of nonionic micellar electrokinetic chromatography with laser-induced fluorescence detection and sweeping as an online preconcentration method was developed for the simultaneous determination of free essential amino acids in supplement formulations. The analytes were derivatized using fluorescein isothiocyanate isomer I dissolved in dimethyl sulfoxide. Optimal separation conditions were achieved using an uncoated fused silica capillary (40.0 cm effective length, 50.2 cm total length, 50 µm internal diameter), 20 mM Na2B4O7, (pH 9.3), 50 mM Brij-35, and 15% (v v-1) methanol as running buffer. Complete separation of all analytes was achieved within 15 min. The optimized method exhibited good linearity (r2 > 0.997), acceptable precision (1.3 – 12.4%), and accuracy (88 – 112%) in concentration range 20 – 1000 ng mL−1. The limit of detection was 6 ng mL−1. The method successfully determined the quantity of free essential amino acids in a dietary supplement containing spirulina.

Impact of structural similarity on the accuracy of retention time prediction

Quantitative Structure-Retention Relationships offer a valuable tool for de-risking chromatographic methods in relation to newly formed or hypothetical compounds, arising from synthetic processes or formulation activities. They can also be used to identify optimal separation conditions, or in support of structural elucidation. In this contribution, we provide a systematic study of the relationship between the accuracy of the retention model, the size of the training set and its structural similarity to the predicted compound. We compare structural similarity expressed either on a fingerprint basis (e.g., Tanimoto index), or by Euclidean distance calculated from of subset of molecular descriptors. The results presented indicate that accurate and predictive models can be built from a small dataset containing as few as 25 compounds, provided that the training set is structurally similar to the test compound. When the training set contains compounds selected by minimizing the Euclidean distance calculated from 3 descriptors most correlated with the retention time, root mean square error of 0.48 min and correlation coefficient of 0.9464 were observed for the test sets of 104 compounds. Moreover, these models meet the Tropsha predictivity criteria. These findings potentially bring the prediction of retention times within the practical reach of pharmaceutical analysts involved in chromatographic method development. We also present an optimisation approach to select algorithm settings in order to minimize the prediction error and ensure model predictivity.

Extraction of the cefluosil from rare earth slag by pressurized filtration

Bayan Obo blast furnace slag (i.e., rare earth slag) is rich in rare earth elements. However, current methods for the separation and extraction of rare earth elements often suffer from lengthy production processes, high energy consumption, and significant environmental pollution, making large-scale applications difficult. Therefore, the separation, purification, and comprehensive utilization of rare earth elements from rare earth slag have become urgent priorities. In this study, gas pressure filtration technology was employed to purify and separate cerium fluorosilicate crystals from a quaternary system of CaO-SiO2-CaF2-Ce2O3 rare earth slag. The pressure filtration mechanism was investigated, and both constant rate filtration and constant pressure filtration cake models were established. Additionally, the nucleation behavior of the cefluosil crystals was studied, and the optimal nucleation temperature under theoretical conditions was estimated to be 1145 °C. Furthermore, the effects of different separation conditions on the separation efficiency were examined, and it was concluded that successful separation of the cefluosil crystals was achieved under the optimal separation conditions (i.e., filtration temperature of 1150 °C, filtration pressure of 0.35 MPa, and filtration times of 4). After the pressure filtration separation, the recovery rate of Ce, a rare earth element, in the upper crucible reached 88.83%. This study confirms the effectiveness of pressure filtration for solid-liquid separation of rare earth slag and provides new insights for the separation and purification of high-value rare earth elements in rare earth slag.

Separation and antioxidant activity of the water-soluble yellow monascus pigment and its application in the preparation of functional rice noodles

Herein, the purification of the water-soluble yellow Monascus pigment from fermentation broth using the LX3020 resin is reported. The resin adsorbed the pigment via chemisorption involving hydrophobic and electrostatic interactions. The optimal operating conditions for the dynamic separation of pigment are 25 °C, a feed solution pH of 4.0, 70% (v/v) ethanol as eluent, and an adsorption and elution flow rate of 1 B V/h. The purity and recovery rate of this pigment were 100% and 22.4%, respectively. Antioxidant activity assays showed that the antioxidant capacity of the pigment (2.5 mg/mL) reached 64.2% of that of vitamin C units. Its free radical scavenging capacity is good, and it can protect against H2O2-induced cell oxidative injury with no cytotoxicity. Therefore, utilization of this pigment (120 mg/100 g) to manufacture functional rice noodles with improved texture qualities and sensory indexes. The degree of rice noodle contamination decreased by ∼90% after cultivation for 48 h. These results reveal that yellow Monascus pigment could play an important role in the preparations of functional foods.

A pilot study on recovery of iron from sulfur-bearing hematite ore using hydrogen-based mineral phase transformation followed by magnetic separation

Sulfur is a harmful impurity in iron ore, which seriously affects the subsequent smelting process and product quality. In this study, a novel process of hydrogen-based mineral phase transformation followed by magnetic separation was proposed to treat sulfur-bearing refractory iron ore. The results of pilot-scale experiments showed that in the oxidation heating stage, the sulfur element in the ore was oxidized to form SO2. During the reduction roasting stage, the hematite within iron ore powder was almost entirely transformed into magnetite at a reduction temperature of 520 °C using a gas combination of 45 % H2- 15 % CO- 40 % N2, which significantly enhanced the magnetism of the particles. At this time, iron minerals could be effectively recovered by a grinding and low-intensity magnetic separation process. Under the optimum roasting and magnetic separation conditions, the iron grade of magnetic concentrate reached 66.40 %, the iron recovery was 92.44 %, and the sulfur content decreased significantly from 0.547 % to 0.038 %. The hydrogen-based mineral phase transformation technology showed unique technical advantages and environmental potential in treating sulfur-bearing refractory iron ores.

Opportunities of desalination concentrates for lithium recovery: Optimal separation by synergic solvents

Lithium, highly demanded for its use in the battery industry, among other applications, has become a vulnerable commodity due to shortages in traditional sources. Although it is found in low concentration in SWRO brines, this waste represents a new source of this raw material. Based on previous studies in which Li+ extractions > 95 % were achieved, the optimal separation conditions of lithium from SWRO concentrates by solvent extraction with DBM•TOPO and FDOD•TOPO have been obtained for the first time. To this end, response surface methodology (RSM) with a three-level central composite design (CCD) has been applied. Three process variables, extractant concentration, basicity of the aqueous phase, and molar ratio between extractants, were evaluated using statistical parameters and second-order regression models. The optimized variables achieved maximum predicted extraction values of 99.7 % for DBM•TOPO and 100 % for FDOD•TOPO, not found yet in the open literature. Notably, for FDOD•TOPO system the needed pH for extraction is reduced, and both systems require a DBM:TOPO and FDOD:TOPO less than 1, a crucial consideration in terms of cost. This study opens new opportunities for lithium supply through desalination concentrates recovery.

Optimum conditions for high-speed solid-liquid separation by ballasted flocculation.

In the ballasted flocculation, high-speed sedimentation of suspensions is achieved using a microsand as a ballast material and a polymer flocculant combined with microflocs made of polyaluminum chloride (PAC) as an inorganic coagulant. In this study, three turbid water samples containing kaolin clay (kaolin concentration: 20, 200, and 500 mg/L) were treated by coagulation-sedimentation and ballasted flocculation. The effects of pH and PAC dosage, which are the controlling parameters for coagulation, and the microsand (silica sand) and polymer dosages, which are the controlling parameters for ballasted treatment, on the treatment efficiency and floc settling velocity were examined. The floc settling velocity under the optimum conditions was 17 times higher than that of the conventional coagulation-sedimentation process using PAC. The turbidity was 0.54 turbidity unit (TU) (TU as the kaolin standard), and its removal efficiency was 99.7%. Furthermore, turbid water samples with different kaolin concentrations (20 and 500 mg/L) were treated via the ballasted flocculation. In this study, fundamental information on the optimization of each dosage condition of coagulant, ballast, and polymer and pH condition in ballasted flocculation was obtained, and the removal mechanisms under optimal, underoptimistic and overoptimistic conditions were proposed.

Enantioseparation of two antifungal azole drugs by analytical countercurrent chromatography using sulfobutyl ether-β-cyclodextrin as chiral selector

This study reports a successful enantioseparation of two antifungal drugs, Ketoconazole and Voriconazole, using countercurrent chromatography (CCC) with synthesized sulfobutyl ether-β-cyclodextrin (SBE-β-CD) as chiral selector. Two biphasic solvent systems composed of dichloromethane: 0.1 mol L−1 of phosphate buffer solution (pH 3.0) (1:1, v/v) and n-hexane: ethyl acetate: 0.1 mol L−1 phosphate buffer solution (pH 3.0) (1.5:0.5:2, v/v/v) were selected. Influence factors were investigated, including degree of substitution of SBE-β-CD, concentration of SBE-β-CD, equilibrium temperature, and pH of aqueous phase. Under optimized separation conditions, a large enantioseparation factor of α ≥ 3.26 and a high peak resolution Rs= 1.82, was achieved for enantioseparation of Voriconazole by countercurrent chromatography, and purity of two azole stereoisomers collected from CCC separation reached 98.5%, as determined by HPLC. Molecular docking was employed to investigate the formation of inclusion complex.

Synthesis of Green Polyethylene Glycol-Lauric Acid Demulsifier from a Natural Source and Its Application in Demulsification of Field Emulsion: Experimental and Modeling Approach

Summary Green demulsifier was synthesized through an esterification technique by using polyethylene glycol (PEG) and fatty acid (lauric acid). The synthesized demulsifier was characterized through several tests to analyze the functional groups and determined the molecular structure, thermal stability, and biodegradability of the demulsifier molecule. The performance of the synthesized demulsifier was investigated using the standard static bottle test method to break the water-in-oil (W/O) tight emulsion. Optical microscopic and viscosity studies of emulsions were also performed to understand the demulsification process and mechanism. Based on the response surface method (RSM), central composite design (CCD) was used to develop the statistical model of demulsification efficiency by considering the four most influencing factors—demulsifier concentration, water content, settling time, and temperature—and to examine the optimal condition for maximum water separation from the emulsion. The statistical model’s accuracy and significance were evaluated using analysis of variance (ANOVA) and diagnostic plots. The effect of each factor was analyzed through 3D graphs and contour maps. The result indicates that all the factors significantly influenced the demulsification efficiency with a p-value of <0.0001, among which the presence of water is the dominating variable. At the optimal condition, the lauric acid-PEG-demulsifier (LPED) achieves a maximum demulsification efficiency of 95% in 30.9 minutes. Furthermore, the percent absolute deviation was computed after comparing the experimental findings to those predicted by the model and it was observed that the model’s prediction accuracy was >97%. Finally, the biodegradability test results showed that the developed demulsifier is completely biodegradable in 21 days. Because the synthesized demulsifier is eco-friendly and has an excellent dehydration rate, it may be used in the petroleum industry for breaking field-tight emulsions as an alternative to chemical demulsifiers.