Supercritical Fluid Extraction Parameters Research Articles

Supercritical CO2 extraction of solid-state cultivation fungus producing azaphilone polyketides

Supercritical Fluid Extraction (SFE) methods dedicated to microorganisms specialized metabolites are very scarce in the literature and limited to liquid cultivation. We proposed here a new sample preparation method to achieve SFE of specialized metabolites from solid-state cultivation. SFE parameters, including CO2 pressure, temperature of extraction cell and percentage of co-solvent, were optimized in the case of solid-state cultures of Penicillium sclerotiorum SNB-CN111, a filamentous fungus producing azaphilone pigments. The metabolic composition of the extracts was then analyzed by reverse-phase liquid chromatography coupled to electrospray ionization and tandem mass spectrometry in data dependent acquisition mode. The resulting molecular networks generated by MetGem software allowed the annotation of the extracted metabolites in the different conditions, confirming the enrichment of fractions according to the polarity of azaphilone subfamilies. First, the 100 % CO2 fraction a yield ten times higher than hexane maceration The optimization of SFE method led to an extraction yield twice as high as ethyl acetate maceration when mixing CO2 with ethanol and, indicating that CO2/ethanol SFE is more environmentally-friendly and efficient than standard maceration methods for the extraction of azaphilones from solid-state fermentation.

Selection of processing parameters for the integrated supercritical CO2 extraction from green tea leaves and extract impregnation onto starch-chitosan based films

The study aimed toward the development of biocompatible and biodegradable polymeric films (starch-chitosan and starch-chitosan-cyclodextrin) with biologically valuable green tea leaf extract using an environmentally friendly integrated process of supercritical fluid extraction (SFE) and supercritical solvent impregnation (SSI). The SFE-SSI process parameters were selected through the initial estimation of the SFE parameters effect (temperatures 35 and 70 °C and the addition of co-solvents ethanol, ethanol/water, and water). The present early-stage work showed that an increase in temperature increased extraction yield (from 0.9 to 4.2%) and caffeine content while it decreased polyphenolic and pigment content as well as antioxidant activity and extract loading onto films (from 7.1 to 0.1%). The addition of co-solvents to sc-CO2 had an adverse effect on extract yield, composition, and loading. The highest recorded total phenolic, flavonoid, chlorophyll A, and caffeine content in extracts were 136.5 mg GE/g, 22.7 mg RE/g, 8.1 mg/g, and 460.0 mg/g, respectively.

A Comparative Study on Response Surface Optimization of Supercritical Fluid Extraction Parameters to Obtain Portulaca Oleracea Seed Oil with Higher Bioactive Content and Antioxidant Activity Than Solvent Extraction

AbstractPortulaca oleracea (purslane) seed oil is a rich source of omega‐6 and omega‐3 fatty acids. Extraction of the purslane seed oil while preserving its high nutritive quality has been a challenge since conventional solvent extraction has many adverse effects on bioactive content. This study aims the optimization of purslane seed oil supercritical fluid extraction (SFE) conditions and to compare purslane seed oils obtained with SFE and conventional solvent extraction in terms of oil yield, along with the purslane seed oil quality and bioactive content. For this purpose, the SFE process parameters (pressure, temperature, static time, and dynamic time) are optimized for oil yield, omega‐6, omega‐3, and antioxidant activity using response surface methodology (RSM). Optimum SFE pressure, temperature, static time, and dynamic time levels are determined as 350 bar, 50 °C, 20 min, and 90 min, respectively. Oil yield and physicochemical quality properties of conventional solvent extract and SFE samples are determined and compared. Consequently, samples obtained via SFE and solvent extraction have similar quality properties. Distinctly, SFE allows an extraction with 5.6% higher total phenolic compound (TPC) and 33% higher antioxidant activity than solvent extraction.Practical Applications: In the study, the extraction of purslane oil using supercritical fluid extraction is optimized with different approaches. At optimum conditions, purslane oil is extracted and all physicochemical properties and the process efficiency (yield) are compared with the solvent‐extracted samples. The results of this study make supercritical fluid extraction of purslane seed oil possible since all optimum operating conditions of a pilot‐sized extractor are reported in the study. It is believed that the results provide a good starting point for industrial operations. Moreover, researchers also believe that research studies unveiling the new potential oil‐bearing seeds are important to overcome the vegetable oil shortage that emerged this year.

Isolation of Cherry Seed Oil Using Conventional Techniques and Supercritical Fluid Extraction.

This study aims to compare the suitability of three extraction techniques (cold pressing, Soxhlet and supercritical fluid extraction (SFE)) to isolate oil from cherry seeds. Oils were examined in terms of extraction yield, fatty acids profile, tocopherols yield and antioxidant activity. Additionally, influence of SFE parameters was evaluated using one-factor-at-a-time design with pressure (200-350 bar), temperature (40-70 °C), flow rate (0.2-0.4 kg/h) and particle size (<800 µm and >800 µm). Oil yields ranged from 2.50% to 13.02%, whereas the highest yield was achieved with SFE. Samples were rich in polyunsaturated fatty acids, regardless of the applied extraction technique. The main fatty acids were linoleic (46.32-47.29%), oleic (40.89-41.65%), palmitic (6.56-8.00%) and stearic (2.21-2.30%) acid. Total tocopherols yield was between 16.63 mg/100 g oil and 60.61 mg/100 g oil, and highest yield was achieved with SFE. Among the tocopherols, γ-tocopherol was the most abundant, followed by α-, δ- and β-tocopherol. Antioxidant activity was determined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic) cation (ABTS) assays, and the results indicated that SFE extracts exhibited better or comparable antioxidant potential compared to traditional techniques. The comparison between modern and conventional extractions for oil recovery demonstrates pros and cons for the possibility of industrial application.

Experimental optimization of the supercritical fluid extraction of triterpenoids from Acacia dealbata Link. Leaves

Acacia dealbata Link. is an invasive species with a negative impact on forest production areas. Its removal generates large amounts of residues (biomass) that can be burned for energy production or extracted to obtain high-value compounds, such as triterpenoids of the lupane, ursane and oleanane families, with known bioactive properties. The extraction can be performed with conventional organic solvents or by supercritical fluid extraction (SFE) with CO2 which is a greener alternative. In this work, SFE of A. dealbata Link. leaves was studied in order to identify and optimize the SFE parameters (pressure: 200–300 bar; temperature: 313.15–353.15 K; and addition of ethyl acetate as cosolvent: 0–10 wt%) that enhance productivity and selectivity towards specific triterpenoids. Even though Soxhlet extraction with dichloromethane provided higher total extraction yield (ηTotal = 3.8 wt% versus 2.1–3.2 wt%, for SFE), SFE surpassed Soxhlet results in terms of individual yields and concentrations of squalene, α-tocopherol, α-amyrone, β-amyrone, and lupenone. For these five compounds the SFE yield reached 0.8043 wt% and the extract concentration reached 35.5 wt% (15.1 % and 95.1 % higher than with Soxhlet extraction, respectively). Particular emphasis should be given to lupenone, with a maximum yield of 0.4748 wt% and a concentration of 22.9 wt% in the SFE extracts obtained at 250 bar, 313.15 K and no cosolvent (ethyl acetate). The optimum conditions of pressure, temperature and ethyl acetate content depended on the response. Productivity, ηTotal, was maximized by increasing all three factors to its maximum conditions. Temperature was one of the most impactful parameters on the individual triterpenoids SFE yields with lower temperatures enhancing the selectivity.

Comparison of two extraction methods for the determination of organolead compounds using sodium tetrapropylborate as derivatization reagent

Two extraction methods of accelerate solvent extraction (ASE) and supercritical fluid extraction (SFE) were used to the extraction of trimethyl lead (TML) and triethyl lead (TEL), which were detected by gas chromatographer coupled with mass spectrometry. Sodium tetrapropylborate, as the derivatization reagent, was applied for the detection of gas chromatography. The recovery rate of ASE were about 88.2% (TML) and 86.4% (TEL) with 15 min consuming. The recovery rate of SFE were about 93.7% (TML) and 94.1% (TEL) with 40 min consuming. Two extraction methods of ASE and SFE were optimized, which were also analyzed in recovery, repeatability, accuracy, limit of detection (LOD) and other aspect. Both ASE and SFE exhibited rational recovery efficiency. The established methods were also applied to the real soil samples. SFE had better extraction effect according to time consumption, recovery rate, LOD and accuracy. However, ASE had more advantages in automated extraction, which could be applied to the pretreatment of large amounts of samples. • Trimethyl lead and triethyl lead of soil environment are extracted and measured. • ASE / SFE - GC system is established for the assessment of trimethyl lead and triethyl lead. • Experimental parameters of ASE and SFE are evaluated and optimized. • Difference and efficiency of ASE and SFE are analyzed for practical application.

Comparison of response surface methodology (RSM) and artificial neural network (ANN) modelling for supercritical fluid extraction of phytochemicals from Terminalia chebula pulp and optimization using RSM coupled with desirability function (DF) and genetic algorithm (GA) and ANN with GA

In the present study supercritical fluid extraction parameters for extraction of phytochemicals from Terminalia chebula (Haritaki) pulp were optimized using different approaches and compared. A central composite rotatable design (CCRD) was employed with four numerical factors viz. temperature, pressure, time and co-solvent flow rate. The responses were total phenol content (TPC), total flavonoid content (TFC) and antioxidant activity (2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity) of the extracts. Two different methods viz. response surface methodology (RSM) and artificial neural network (ANN) were used for modelling from the same set of experiments. Subsequently, optimization was carried by three different approaches viz. RSM coupled with numerical optimization by desirability function (RSM-DF), RSM coupled with genetic algorithm (RSM-GA) and ANN coupled with genetic algorithm (ANN-GA). Statistical analyses indicated that the models derived using both the methods i.e., RSM and ANN can be used to predict the response precisely, but RSM (R2 = 0.9987) method was somewhat found to be superior compared to ANN model (R2 = 0.9973). When comparing the optimization approaches, it was observed that results obtained from all the approaches were close to each other, but RSM-GA and RSM-DF approaches provided higher values of TPC, TFC and DPPH radical activity compared to ANN-GA approach. The values of TPC (mg GAE/mL), TFC (mg QE/mL) and DPPH (%) for RSM-GA were 428.03, 136.58, 92.63 respectively, for RSM-DF were 432.28, 137.36, 92.54 respectively and for ANN-GA were 414.25, 135.55, 91.32 respectively. From the present study it can be concluded that both RSM and ANN can be used for modelling of the processes with good predictability and optimization can be done using different approaches which will depend upon the specific process or the problem.

Pilot-scale supercritical CO2 extraction coupled molecular distillation and hydrodistillation for the separation of essential oils from artemisia argyi Lévl. et Vant

ABSTRACT The essential oils of Artemisia argyi Lévl. et Vant were extracted and separated using three methods, hydrodistillation (HD), supercritical fluid extraction (SFE), and SFE coupled molecular distillation (SFE-MD). Various extraction parameters of SFE were optimized by process modeling of Hansen solubility parameters which are 30 MPa, temperature 45°C, no co-solvents, extraction time 2 h, and flow rate of 90 kg/h. The essential oils obtained by HD and SFE-MD have similar major compositions. The antimicrobial activities were examined according to the agar well diffusion method and the minimum inhibition concentrations against Staphylococcus aureus and Escherichia coli were compared.Abbreviations A. argyi, Artemisia argyi; CFU, Colony Forming Unit; DMSO, dimethylsulfoxide; E. coli, Escherichia coli; GC-MS, Gas Chromatography-Mass Spectrometer; HD, hydrodistillation; HSP, Hansen solubility parameters; MIC, minimum inhibition concentration; OSE, organic solvents extraction; RSM, response surface methodology; SCCO2, supercritical-CO2; SFE, supercritical fluid extraction; SFE-MD, SFE coupled molecular distillation; SMILES, Simplified Molecular Input Line Entry Syntax; S. aureus, Staphylococcus aureus;

Response Surface Methodology for Optimization of Supercritical Fluid Extraction of Orange Peel Essential Oil

Background: Orange peel essential oils were obtained using supercritical fluid extraction. This method is an important high scaling extraction method used for the extraction of plant and animal extracts. Objectives: The aim of this study was the optimization of the extraction of the orange peel essential oil. Methods: The experimental parameters of Supercritical Fluid Extraction (SFE) such as temperature, pressure, and extraction time, and modifier volume were optimized using a central composite design after a 24-1 fractional factorial design. Orange peels were collected from ripe orange and were washed, air dried, and milled. Then, a Suprex MPS/225 system in the SFE mode with a maximal operating pressure of 395 bars was used for essential oil extraction. Moreover, GC-MS and GC-FID were used for the identification and determination of oil compounds, respectively. Results: Eight compounds have been identified based on their retention indices and mass spectra. According to the results, α-pinene, β-pinene, myrcene, d-limonene, terpinolene, C8-aldehyde, citronellol, and linalool were identified in orange peel essential oil. The optimum SFE conditions were obtained at a pressure of 347.07 atm, temperature of 55° C, extraction time of 30.16 min, and ethanol volume of 147.05 µL. Moreover, extraction yields based on SFE varied in the range of 0.04% to 1.18% (w/w). Conclusion: The Results showed supercritical fluid technology as the best alternative technique for the extraction of pure and high-quality essential oil from orange peel. It is a green method and does not have any environmental impact.

Preparation of Withaferin A nanoparticles extracted from Withania somnifera by the expansion of supercritical fluid solution

Withania somnifera (L.) Dunal. is a plant with several important medicinal properties that have long been used in traditional therapy to treat some diseases. Micronisation reduces the particle size, which increases the bioavailability. In this study, due to the great potential of Withaferin A in the treatment of diseases, the nanoparticle formation of Withaferin A extracted from Withania somnifera, was considered. In the first step, the experimental parameters of supercritical fluid extraction of W. somnifera were optimised by central composite design (CCD). Then, the herbal extract was micronised using a new, repeatable, and robust method in terms of the expansion of carbon dioxide supercritical solvent. Also, the parameters of the experiment were optimised with the Draper-Lin small composite designs. Moreover, we identified Withaferin A nanoparticle in the extracted samples by utilising liquid chromatography-mass spectrometry (LC-MS) and the obtained precipitates were characterised using field emission scanning electron microscopy (FESEM). The optimal conditions of the experiment were as follows: pressure drop 254 atm, at the temperature of 53°C, equilibrium time 23 min, and collection time 57 min. Based on the observed results, the optimum points for the size and number of Withaferin A nanoparticles were predicted as 5 and 5842 nm, respectively. The nanoparticle production was accomplished through the expansion of supercritical solution, while the speed of expansion was much lower compared to the ordinary rapid expansion of supercritical solution (RESS) methods. Also, the nanonisation conditions, especially the pressure drop, significantly affected the formation of nanoparticles.

Influence of supercritical fluid extraction parameters in preparation of black chokeberry extracts on total phenolic content and cellular viability.

Black chokeberries (Aronia melanocarpa), deciduous shrubs of the Rosaceae family, are native to northeastern North America. Chokeberry fruits are cultivated to make jellies, juices, and wines. Black chokeberry pulp is rich in phenolics and other antioxidants and exhibits potential for health and food packaging benefits. Chokeberries’ in vitro antioxidant activity is among the highest values of all berries, though chokeberry extraction techniques frequently employ environmentally unfavorable solvents or are time‐inefficient. Batch extraction of antioxidants from chokeberry pomace using supercritical carbon dioxide with an ethanol modifier was used to examine the effects of plant loading, pressure, temperature, and percent ethanol by weight. Effects on total phenolic content (TPC) and the optimal conditions for extractions within these ranges are reported. Multivariate analyses reveal the following relationships of extraction conditions upon TPC: Temperature is directly proportional, percent ethanol by weight is inversely proportional, and chokeberry loads can be increased to enhance antioxidant activity, though not through a linear relationship. In studies involving 0.5 g plant load, the conditions 24.9MPa, 68°C, 90wt‐% CO2, and 10wt‐% ethanol generated the highest TPC value, 3.42 ± 0.20 mg gallic acid equivalents/gram chokeberry. Chokeberry extracts displayed antiproliferative effects on the SKBr3 breast cancer line and the 52KO MEF line, although TPC was not predictive of cellular responses. HPLC‐MS data suggest cyanidin hexose and cyanidin pentose compounds as well as quercetin deoxyhexose–hexose as components of the more favorable extraction product that reflected a significant decrease in viability for the extract in comparison with ethanol control in the SKBr3 breast cancer line.

Evaluation of supercritical fluid extraction for the determination of neonicotinoid pesticides in green onion

A supercritical fluid extraction (SFE) method was presented for the determination of neonicotinoid pesticides in green onion. We optimized the SFE parameters, namely the pressure, temperature, type and concentration of the modifier solvent, and extraction time, by testing on the incurred green onion applied with four commercial neonicotinoid formulations at the harvesting stage. The analytical values of the four neonicotinoids, obtained by 5 min dynamic SFE with a 25% (v/v) methanol/supercritical carbon dioxide mixture at 80 °C and 25 MPa, were in good agreement with those obtained by solid-liquid extraction using a homogenizer. This latter homogenization method is employed as a Japanese official method for the analysis of pesticide residues in food. The SFE-to-homogenization analytical value ratios were in the range 98.8–100.0%. Spike-and-recovery testing with spiked green onion was also performed by optimized SFE. The ratios of the analytical-to-spiked concentrations for six neonicotinoids obtained by the SFE method were 96.1–102.1% for 0.4 mg/kg and 93.9–104.1% for 4.0 mg/kg spiking levels. These values satisfied the Japanese validation guidelines for the testing method of pesticides in food. These results indicate that SFE is applicable for the analysis of neonicotinoids in green onion and enables automatic extraction with a small amount of solvent.

Optimization of the Ratio of ω-6 Linoleic and ω-3 α-Linolenic Fatty Acids of Hemp Seed Oil with Jackknife and Bootstrap Resampling

Abstract In the present work, supercritical fluid extraction (SFE) of hemp (Cannabis sativa) seed oil at various ranges of SFE parameters is performed. These parameters and respective ranges are temperature (40–80) °C, pressure (200–350) bar, solvent (CO2) flow rate (5–15) g/min, particle size (0.43–1.02) mm and amount of co-solvent (ethanol) (0–10) % of solvent flow rate. Central composite design (CCD) suggests 32 experimental runs to perform through SFE. The obtained oil is analysed through gas chromatography to identify its fatty acids concentrations. The ratio of ω-6 linoleic and ω-3 α-linolenic fatty acids (ω-6/ω-3) is optimized through CCD to obtain the desired amount of 3:1 as this ratio is highly preferred for various health benefits. Ratio of ω-6/ω-3 is obtained in the range from 2.11 to 3.06:1 for all experimental runs. The effect of SFE parameters on this ratio is investigated. Further, cross-validation is peformed on the experimental data obtained for the concentrations of both fatty acids by jackknife and bootstrap resampling to authenticate the obtained data. Small value of standard deviation (~1), less standard error of the mean (SEM) (<0.8) and less variance coefficient (<0.11) confirms the validity of the obtained data. All the estimators’ values such as standard deviation, variance coefficients and SEM are observed in 95 % of confidence intervals.

Supercritical fluid extraction in isolation of cyclitols and sugars from chamomile flowers.

The aim of the present study was to develop an optimization procedure for supercritical fluid extraction parameters, in order to obtain the highest possible yield of sugars and cyclitols from plant material. Response surface methodology based on Box-Behnken design was applied to evaluate the effect of: temperature (40, 60, 80°C), pressure (100, 200, 300bar), and co-solvent (methanol) percentage (20, 25, 30%). As a result of the optimization process, we found that the highest amount of sugars (15.02 mg/gof dried material) and cyclitols (0.86 mg/g of dried material) was obtained when the following parameters were applied: 80°C, 228 bar, and 30% of methanol. Moreover, co-solvent concentration and temperature had a higher influence onto the obtained amounts compared with the pressure.

Preparation of High-quality Glabridin Extract from Glycyrrhiza glabra

Supercritical fluid extraction (SFE) using cosolvent-modified supercritical carbon dioxide and a two-step separation/purification method was investigated as a way to improve the purity of glabridin, one of the many bioactive components of Glycyrrhiza glabra (licorice). The SFE parameters were optimized using an analytical-scale SFE system in the temperature range 40–80°C and the pressure range 10–50 MPa. The extraction was then scaled up by 100 times using a preparative SFE system under the following set of optimized conditions: 40°C, 30 MPa, and SCCO2 modified with ethanol equivalent to its 25% (v/v) concentration. The glabridin purity obtained through the scaled-up SFE system was 6.2%, a much higher level than that obtained through organic solvent extraction. The licorice extract obtained by scaling up the SFE system was isolated and purified by applying alcohol precipitation/ filtration and adsorption chromatography with 80% aqueous ethanol to obtain a purer product. It was confirmed that the glabridin purity of the final extract product was increased by up to 37%, without significant loss of glabridin after two separation/purification steps.

Comparative study of different extraction processes for hemp (Cannabis sativa) seed oil considering physical, chemical and industrial-scale economic aspects

Hemp (Cannabis sativa) seed oil is a rare source of nourishment for vegetarian diets due to the unique ratio of ω-6/ω-3 fatty acid as 3:1. It is beneficial for cardiovascular health, skin, hormonal balance, diabetes, etc. These oil benefits encourage the chemical industries for its intensive extraction to accomplish the quantity and quality of the product. Despite being various processes i.e. supercritical fluid extraction, Soxhlet, percolation, ultrasonication, pyrolysis, pretreatment processes etc., none of above is the best in all aspects. Therefore, the present study investigates different extraction processes for hemp oil and compared its industrial-scale economic assessment, extraction yield, oil compositions and physico-chemical properties. Central composite design was employed to optimize the parameters of supercritical fluid extraction and ultrasonication processes. Quadratic models (P < 0.05) for both processes were developed with satisfactory R2 (>0.93). The maximum yield of 37.30% was estimated through ultrasonication treated Soxhlet process. Gas chromatography-mass spectrometry demonstrated Soxhlet as the best-suited process while offering the optimum ω-6/ω-3 ratio. Further, gas chromatography-mass spectrometry of hemp bio-oil obtained through pyrolysis identified the volatile and flammable materials to assure its suitability as bio-fuel. Economic analyses for different processes revealed supercritical fluid extraction as the most beneficial followed by Soxhlet, ultrasonication, ultrasonication treated Soxhlet and Soxhlet treated ultrasonication.

Impact of Grinding Procedure on the Yield and Quality of the Extract from Clove Buds Using Supercritical Fluid Extraction

Introduction: The effects of the grinding procedure on the supercritical fluid extraction (SFE) yields of eugenol, β-caryophyllene, α-humulene, and eugenyl acetate from clove are discussed in detail in this paper. Methods: For this purpose, five grinding procedures were employed: 1) continuous 1-min grinding, 2) continuous 2-min grinding, 3) two 1-min grinding periods with 6-min stop in between 4) continuous 4-min grinding, and 5) four 1-min grinding periods with 6-min stops in between. After that, the extractor was filled with 12 g of milled clove obtained using one of the grinding procedures while the other SFE parameters were kept constant (pressure of 150 bar, temperature of 40 °C, supercritical CO2 flow rate of 1.03×10−4 kg/s, static time of 20 min, and dynamic extraction time of 15 min). Then, the composition of the extract was evaluated by gas chromatography (GC). Conclusion: It was found that the grinding procedure has considerable effects on the recoveries of eugenol, β-caryophyllene, α-humulene, and eugenyl acetate from clove, and employing four 1-min grinding periods with 6-min stops in between as the grinding procedure gave the highest content of the aforementioned components in the extract.

Overview on the Application of Modern Methods for the Extraction of Bioactive Compounds from Marine Macroalgae

Marine macroalgae represent a rich source of bioactive compounds that can be implemented in various food, cosmetic, and pharmaceutical products for health improvement. It has been proven that these bioactive compounds, such as polyphenols, polysaccharides, carotenoids, and ω-3 fatty acids possess bioactivity. For the extraction of these compounds, modern methods (Supercritical Fluid Extraction (SFE), Subcritical Water Extraction (SWE), Ultrasound-Assisted Extraction (UAE), and Microwave-Assisted Extraction (MAE)) have been used due to their advantages over the conventional methods. The process parameters of each method must be optimized for obtaining the extracts with the targeted bioactive compounds. In distinction from the existing reviews, the present review provides novelty with respect to: (a) presenting systematically the selected process parameters of SFE (temperature, time, pressure, use of co-solvents), SWE (temperature, time, pressure, solid-solvent ratio), UAE (temperature, time, frequency, power, solid-solvent ratio), and MAE (temperature, time, frequency, power, solvent type) applied for the extractions of marine macroalgae; (b) reporting the major groups or individual compounds extracted with their biological activities (if determined); and, (c) updating available references.

Optimization of operational parameters of supercritical fluid extraction for PHCs removal from a contaminated sand using response surface methodology

Supercritical fluid extraction (SFE) was applied to investigate the removal of petroleum hydrocarbons (PHCs) from a contaminated soil. The sand spiked with diesel fuel with a ratio of 5 wt% was used for this study. The effects of SFE operational parameters including fluid pressure, fluid temperature, time duration and mode of extraction on the removal efficiency of PHCs were investigated. SFE experiments were performed at different levels of pressure (15, 33 and 50 MPa) and temperature (30, 75 and 120 °C). Static mode and combination modes at various time duration were performed. Among them, the combination of 10 min static mode followed by 10 min dynamic mode, repeated for 3 cycles for a total time of 60 min resulted in the highest PHCs removal percentages. In addition, factorial design and response surface methodology (RSM) were applied to optimize the effect of pressure and temperature. According to RSM, the optimum pressure and temperature were found to be 50 MPa and 69.3 °C, respectively. The best combination of pressure and temperature based on experimental results was determined to be at 33 MPa and 75 °C; which resulted in the highest extraction rates of 99.2%, 91.7% and 86.1% for PHC F2, F3 and F4 fractions, respectively. In general, increasing pressure at constant temperature resulted in higher PHC removal rates, however, increasing temperature at constant pressure did not necessarily lead to higher PHC removal percentages and there is an optimum range for temperature.

Determination of major aromatic constituents in vanilla using an on-line supercritical fluid extraction coupled with supercritical fluid chromatography.

An on-line supercritical fluid extraction coupled with supercritical fluid chromatography method was developed for the determination of four major aromatic constituents in vanilla. The parameters of supercritical fluid extraction were systematically investigated using single factor optimization experiments and response surface methodology by a Box-Behnken design. The modifier ratio, split ratio, and the extraction temperature and pressure were the major parameters which have significant effects on the extraction. While the static extraction time, dynamic extraction time, and recycle time had little influence on the compounds with low polarity. Under the optimized conditions, the relative extraction efficiencies of all the constituents reached 89.0-95.1%. The limits of quantification were in the range of 1.123-4.747μg. The limits of detection were in the range of 0.3368-1.424μg. The recoveries of the four analytes were in the range of 76.1-88.9%. The relative standard deviations of intra- and interday precision ranged from 4.2 to 7.6%. Compared with other off-line methods, the present method obtained higher extraction yields for all four aromatic constituents. Finally, this method has been applied to the analysis of vanilla from different sources. On the basis of the results, the on-line supercritical fluid extraction-supercritical fluid chromatography method shows great promise in the analysis of aromatic constituents in natural products.