The properties of the supercritical fluid near the critical point can be changed by varying the pressure and temperature, allowing selective and faster extraction. Supercritical fluids exhibit ...liquid-like density and gas – like viscosity & diffusion coefficients and can penetrate more into the solid matrix inaccessible to liquids due to negligible surface tension and viscosity. They are suitable as a substitute for organic solvents in a range of industrial and laboratory processes. These properties of supercritical fluids are well suited for the extraction of solutes, from various plants, fruits, flowers, seeds, leaves, which cannot be easily extracted using conventional extraction processes. In view of above mentioned advantages, supercritical fluid extraction is becoming increasingly popular in many industries such as petroleum, chemical, food, and perfumery. Supercritical fluids are also used for the extraction of metal ions from aqueous solutions and solid and liquid matrices.This review paper provides a concise review of the applications of supercritical fluids from the perspective of feed materials, type of supercritical fluids, co solvents and modifiers used, nature of work, operating conditions, findings, limitations of the work done and scope for further research. The application of supercritical fluids in extraction and purification of various natural extracts and others, using CO2 accounts for more than 90% of the published research in the field of supercritical fluid technology. Other supercritical fluids being used are propane, hexane and butane. Carbon dioxide is a relatively non-polar solvent but has some limited affinity with polar molecules due to its large molecular quadrupole. Co-solvents and modifiers are often be added to improve the solubility of polar molecules. On addition of various co solvents and modifier such as isopropyl alcohol and ethanol, n-hexane, heptane, pentane, toluene, methanol, acetone, formic acid with ammonium formate in methanol etc enhances the performance of supercritical extraction process. Despite this, the status of supercritical fluid technology commercialization is less than satisfactory. A review studies revealed that most of the published research is at laboratory scale with little or no information on scale up and design strategies. Keywords: Supercritical fluids, Carbon dioxide, Co solvents, Modifier, Extraction
•Experimental design for process parameters.•Application of screening designs in Supercritical Fluid Extraction.•Application of optimization designs in Supercritical Fluid Extraction.•Strategies and ...recommendation of experimental design study in Supercritical Fluid Extraction.
Supercritical fluid extraction (SFE), a sustainable green technology leads a wide range of applications since the past decade. Like many other processes, SFE is sometimes criticized for its large number of factors which need to be properly adjusted before every single run. Experimental design and proper statistical analysis with small number of trials in adjusting the SFE parameters become popular in this regard. This paper is aimed to review the common experimental designs that are frequently used in the SFE process. Utilizations of different experimental designs in SFE with the intention of either screening the most influential factors or optimizing the selected factors are briefly reviewed. Strategies and recommendation addressing the choice of appropriate design, constructing design matrix, experimental trial and data analysis are discussed in this paper. For more application oriented readers of SFE, an effective and easy chart on choosing proper experimental design and a list of experimental design software are also included.
In this work, a preparative supercritical fluid chromatography (SFC) method was first developed to separate a series of chiral compounds evaluated as lactam‐based P2RX7 antagonists. Subsequently, ...high‐performance liquid chromatography, SFC, and capillary electrophoresis (CE) were comparatively investigated as QC tools to determine the enantiomeric purity of the separated isomers, including analytical performance and greenness. The screening of the best conditions was carried out in liquid and SFC on the nine derivatives and the amylose tris(3,5‐dimethylphenylcarbamate)‐based chiral stationary phase was found to be highly efficient. The same screening was carried out in CE and very different conditions, either in acidic or basic background electrolyte and different cyclodextrins used as chiral selectors, allowed the separation of six of the nine derivatives. 1‐((3,4‐Dichlorophenyl)carbamoyl)‐5‐oxopyrrolidine‐2‐carboxylic acid (compound 1) was chosen as a probe, and its semi‐preparative separation by SFC and enantiomeric verification using the three techniques are presented. Its limit of detection and limit of quantification are calculated for each method. Finally, the greenness of each quality control method was evaluated.
Supercritical fluid technologies offer a propitious method for drug discovery from natural sources. Such methods require relatively short processing times, produce extracts with little or no organic ...co-solvent, and are able to extract bioactive molecules whilst minimising degradation. Supercritical fluid extraction (SFE) provides a range of benefits, as well as offering routes to overcome some of the limitations that exist with the conventional methods of extraction. Unfortunately, SFE-based methods are not without their own shortcomings; two major ones being: (1) the high establishment cost; and (2) the selective solvent nature of CO₂, i.e., that CO₂ only dissolves small non-polar molecules, although this can be viewed as a positive outcome provided bioactive molecules are extracted during solvent-based SFE. This review provides an update of SFE methods for natural products and outlines the main operating parameters for extract recovery. Selected processing considerations are presented regarding supercritical fluids and the development and application of ultrasonic-assisted SFE methods, as well as providing some of the key aspects of SFE scalability.
•Publications that appeared in 2014 on polymers and supercritical fluids are reviewed.•Ten different application areas are discussed.•Perspectives are provided on miscibility, polymerization, and ...formation of particles, nanocomposites, membranes and porous scaffolds and foams.
A critical overview of publications on applications of supercritical fluids in polymer formation, modification and processing is presented. The review is focused on publications that appeared in 2014 only with the intent of providing an in-depth look at the activity in the most recent year to gain insights on the more recent trends and opportunities. The articles have been grouped under ten different application areas which include (1) polymer solutions and phase behavior, (2) polymerizations, (3) particle formation/micronization/drug delivery systems, (4) films, (5) fibers, (6) membranes, (7) nanocomposites, (8) porous materials – foams/scaffolds, (9) organogels, and (10) lignocellulosic polymers. In each category, articles are discussed under specific polymer or polymer type to better highlight those polymers that are receiving the greater level of attention. In 2014, more polymers were explored for their foamability, and for generation of nanocomposites. Poly(ɛ-caprolactone), poly(lactic acid) and poly(lactide-co-glycolide) were the most frequently investigated polymers for their porous matrix formation, or particle formation features using supercritical carbon dioxide because of their biomedical significance as biodegradable platforms for tissue engineering scaffolds and drug delivery devices. Poly(ethylene oxide), poly(lactic acid), and poly(methyl methacrylate) were the polymers that were explored in multiple application areas.
Based on the close examination of these publications, the review provides specific observations on the advances that are made toward improved understanding of the factors that affect the miscibility of polymers in carbon dioxide, and for further understanding of the synergistic or other effects of components in polymer blends and composites, including the consequences of the presence of crystalline versus amorphous domains and morphological differences, or the consequences of the presence of nanofillers in different applications. New perspectives that are emerging in each application area are presented.
Pressure fluctuations and resulting refractive index changes, induced by the back pressure regulator (BPR) can be a significant source of UV detector noise in supercritical fluid chromatography ...(SFC). The refractive index (RI) of pure carbon dioxide (CO
2) changes ≈0.2%/bar at the most commonly used conditions in supercritical fluid chromatography (SFC) (40
°C and 100
bar), compared to 0.0045%/bar for water (CO
2 IS 44× worse). Changes in RI cause changes in the focal length of the detector cell which results in changes in UV intensity entering the detector. The change in RI (ΔRI/bar) of CO
2 decreases 8-fold at 200
bar, compared to 100
bar. A new back pressure regulator (BPR) design representing an order of magnitude improvement in the state of the art is shown to produce peak to peak pressure noise (PN
p–p) as low as 0.1
bar, at 200
bar, and 20
Hz, compared to older equipment that attempted to maintain PN
p–p
<
1
bar, at <5
Hz. With this lower PN
p–p, changes in baseline UV offsets could be measured as a function of very small changes in pressure. A pressure change of ±1
bar at 100
bar, common with some older BPR's, produced a UV baseline offset >0.5
mAU. A pressure change of ±0.5
bar representing the previous state-of-the-art, resulted in a UV offset of 0.3
mAU. Baseline noise <0.05 is required to validate methods for trace analysis. The new BPR, with a PN
p–p of 0.1
bar, demonstrated UV peak to peak noise (N
p–p)
<
0.02
mAU with a >0.03
min (10
Hz) electronic filter under some conditions. This new low noise level makes it possible to validate SFC methods for the first time.
Metconazole is one of the widely‐used chiral triazole fungicides in controlling wheat leaf rust, powdery mildew, Fusarium head blight with high efficacy, and so forth. In the current work, the ...effects of chiral stationary phases, alcoholic modifiers, and column temperature on the chiral separation of metconazole were discussed in detail. Amylose tris(3,5‐dimethylphenylcarbamate)‐coated chiral stationary phase exhibited much stronger chiral recognition ability toward metconazole stereoisomers in the CO2/ethanol mixture as compared to the others. Then, a two‐step semi‐preparative separation of metconazole was performed through supercritical fluid chromatography and high‐performance liquid chromatography, and the enantiomeric excess values of four stereoisomers were achieved over 98%. Moreover, the enantioselective cytotoxicity of cis‐metconazole against HepG2 cells has been investigated, and the order of the cell proliferation toxicity against HepG2 cells was (1R, 5S)‐metconazole > (1S, 5R)‐metconazole > the mixture. Briefly, this study would provide valuable information in the preparative separation of optically pure metconazole products through chromatographic techniques and their environmental risk assessment.
New analytical approach for high-throughput and comprehensive lipidomic analysis of biological samples using ultrahigh-performance supercritical fluid chromatography (UHPSFC) with electrospray ...ionization-mass spectrometry (ESI-MS) is presented in this work as an alternative approach to established shotgun MS or high-performance liquid chromatography-MS. The lipid class separation is performed by UHPSFC method based on 1.7 μm particle-bridged ethylene hybrid silica column with a gradient of methanol–water–ammonium acetate mixture as a modifier. All parameters of UHPSFC conditions are carefully optimized and their influence on the chromatographic behavior of lipids is discussed. The final UHPSFC/ESI-MS method enables a fast separation of 30 nonpolar and polar lipid classes within 6 min analysis covering 6 main lipid categories including fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, sterols, and prenols. Individual lipid species within lipid classes are identified based on positive and negative-ion full-scan and tandem mass spectra measured with high mass accuracy and high resolving power. Developed UHPSFC/ESI-MS method is applied for the analysis of porcine brain extract as a complex lipidomic sample, where 24 lipid classes containing 436 lipid species are identified. The method is validated for the quantitative analysis of lipid species in biological tissues using internal standards for each lipid class. This high-throughput, comprehensive and accurate UHPSFC/ESI-MS method is suitable for the lipidomic analysis of large sample sets in the clinical research.
Interest in the development of extraction of phytochemicals compounds from Clinacanthus nutans has increased in recent years due to its potential applications in food, chemical, and pharmaceutical ...industries. The quality and yield of the phytochemicals are greatly influenced by the extraction method employed as well as other factors. This paper provides an up-to-date overview of traditional (maceration, infusion, and soxhlet), with modern methods (pressurized hot water extraction, supercritical fluid extraction, ultrasound-assisted extraction, and microwave-assisted extraction) to extract phytochemicals compounds from C. nutans. Problems associated with conventional extraction methods have led to a demand for alternatives and indeed several new extraction methods have been developed and refined in the last two decades that can efficiently extract a great variety of valuable bioactive compounds.
A method was established for the separation and determination of triadimefon and its metabolite triadimenol enantiomer residues in major complementary fruit puree for infants and young children ...(banana puree, pineapple puree, and grape puree) by supercritical fluid chromatography. After the samples were extracted with acetonitrile and purified with a solid phase extraction cartridge, Acquity Trefoil CEL2 chiral chromatographic column was adopted for separation, and gradient elution was conducted at the flow rate of 1.0 ml/min under the mobile phase of supercritical carbon dioxide ‐ 0.5% ammonia methanol, the detection wavelength was 220 nm and quantification was conducted with the external standard method. The limits of quantitation of triadimefon and triadimenol enantiomers were both 0.05 mg/kg, the linear ranges were 0.5–50 mg/L, and the linear correlation coefficients were greater than 0.9993. The recoveries in the spiked samples at 0.05, 0.2, and 3.0 mg/kg were from 80.1 to 106%, and the relative standard deviation reached 3.3–7.6%. The method is efficient, rapid, reproducible, and environmentally friendly, enabling accurate analysis of pesticide enantiomers, which can detect the enantiomer residues of triadimefon and its metabolite triadimenol in major complementary fruit puree for infants and young children.
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