Supercritical Fluid Extraction Parameters Research Articles

Supercritical fluid extraction in situ derivatization for simultaneous determination of chloramphenicol, florfenicol and thiamphenicol in shrimp

The applicability of supercritical fluid extraction in situ derivatization was investigated for determination of trace amounts of amphenicols (chloramphenicol, florfenicol and thiamphenicol) in shrimp. Quantification was performed by using electron-capture negative chemical ionisation-gas chromatography/mass spectrometry (NCI–GC/MS). The parameters of supercritical fluid extraction (addition of modifier, temperature, pressure, extraction time and extraction mode) and in situ derivatization (collection solvent and derivatization reagent) were varied with control. The optimum extractions were obtained using 600 μL ethyl acetate as a modifier for supercritical carbon dioxide with static extraction for 5 min, then dynamic extraction for 10 min at 25 MPa and 60 °C. The conditions for in situ derivatization were 200 μL N,O-bis(trimethylsilyl) trifluoroacetamide containing 1% trimethylchlorosilane in 20 mL ethyl acetate as collection solvent. The new method of supercritical fluid extraction in situ derivatization was found to be linear over the concentration range of 20–5000 pg/g, with detection limits ranging from 8.7 to 17.4 pg/g (using the selective ion monitoring mode), with a R.S.D. (relative standard deviation) less than 15.3% (n = 5). Analysis of spiked shrimp samples revealed that matrix had little effect on extraction. The results presented here indicate that supercritical fluid extraction in situ derivatization is for the trace analysis of amphenicol bacteriostats in shrimp samples.

The influence of temperature and pressure factors in supercritical fluid extraction for optimizing nonpolar lipid extraction from buttermilk powder

The milk fat globule membrane, readily available in buttermilk, contains complex lipids claimed to be beneficial to humans. Phospholipids, including sphingolipids, exhibit antioxidative, anticarcinogenic, and antiatherogenic properties and have essential roles in numerous cell functions. Microfiltration coupled with supercritical fluid extraction (SFE) may provide a method for removing triacylglycerols while concentrating these nutritionally valuable lipids into a novel ingredient. Therefore, SFE as a method for phospholipid concentration needs to be optimized for triacylglycerol removal in buttermilk. The SFE conditions were assessed using a general full factorial design; the experimental factors were pressure (15, 25, and 35MPa) and temperature (40, 50, and 60°C). Particularly interesting is that only triacylglycerols were removed from buttermilk powder. Little to no protein loss or aggregation was observed compared with the untreated buttermilk powder. Calculated theoretical values showed a linear increase for lipid solubility as pressure, temperature, or both were increased; however, experimental values showed nonlinearity, as an effect of temperature. In addition, the particular SFE parameters of 35MPa and 50°C displayed enhanced extraction efficiency (70% total lipid reduction).

Effect of Variety and Maturation of Cheese on Supercritical Fluid Extraction Efficiency

Supercritical fluid extraction (SFE) has been utilized by the food industry in many applications to extract, fractionate, and recover compounds from various food matrices. However, little research has been conducted using SFE as an alternative process for producing reduced-fat cheese. Lipids in cheeses may be selectively extracted due to the nonpolar properties of supercritical carbon dioxide (SC-CO2), without leaving residual chemicals as is the case in solvent extraction. The objective of this study was to evaluate the influence on the extraction process due to cheese variety and protein breakdown by age. A Latin square design was utilized to test the extractability of lipids from Parmesan and Cheddar cheeses, aged young (9-10 months) or old (24 months). Extraction took place in a 500 mL SFE vessel using 100 g of grated cheese samples. The SFE parameters of the extraction were 350 bar, 35 degrees C, and supercritical carbon dioxide at a flow rate of 20 g/min for 55 min. Compositional analysis measured all treated samples and controls of total lipids, lipid profiling, total protein, protein/peptide analysis, moisture, ash, and pH. Cheese type was a major variable in fat extraction. The extraction in Cheddar showed an average fat reduction of 53.56% for young cheese, whereas that in old Cheddar was 47.90%. However, young Parmesan was reduced an average of 55.07%, but old Parmesan was reduced at 68.11%, measured on a dry basis. SFE extracted triglycerides and cholesterol, but did not remove phospholipids. This investigation introduces the observations of the effect of Cheddar and Parmesan varieties on SFE, offering data on the important parameters to consider in the design of SFE processes to reduce fat in cheese.

Assessment of Di‐(2‐Ethylhexyl) Phthalate (DEHP) in Municipal and Industrial Sludges of Taiwan by Supercritical Fluid Extraction (SFE) and Gas Chromatography with Electron Ionization Detection

In the present study, DEHP in selected municipal sewage (raw and treated) and industrial sludges of Taiwan was quantified by SFE and GC/EID. As a precursor, the optimal operating parameters of SFE were identified by laboratory experiments using DEHP spiked quartz sand. DEHP extraction efficiency was increased by the addition of modifier i.e. methanol (0.5 mL, 7%). DEHP concentration in all sewage sludge (M‐1 to M‐4) and a textile industry (I‐6) samples were above the limit suggested by the European Union (100 mg/kg). The results suggest that excess DEHP concentration observed in the sewage sludge needs considerable attention before disposal.

Effect of supercritical fluid extraction parameters and clay properties on the efficiency of phenanthrene extraction

Clay soils have specific properties that cause difficulty in the assessment and remediation of contaminated sites. Furthermore, polyaromatic hydrocarbons, when present in soil, are difficult to extract due to their nonpolar, high molecular weight characterization. In this study, the supercritical fluid (carbon dioxide) extraction (SFE) technique, with and without methanol modifier, was used for removal of PAHs (phenanthrene) from kaolinite, illite, and montmorillonite soils. The impact of SFE parameters (fluid pressure, fluid temperature, and time), and of clay properties (such as clay minerals content, initial moisture content, soil porosity or equivalent pores size, clay surface area, cation-exchange capacity, and clay-swelling index) on the removal efficiency of PAHs from clayey soils were investigated. The results of this investigation were used to develop a semi-empirical correlation between the recovery (i.e. the extraction efficiency) at any time and above mentioned parameters and properties.

Comparison of Solid-Phase Microextraction, Supercritical Fluid Extraction, Steam Distillation, and Solvent Extraction Techniques for Analysis of Volatile Consituents in Fructus Amomi

Four sampling techniques, solid-phase microextraction (SPME), supercritical fluid extraction (SFE), steam distillation (SD), and solvent extraction (SE), were compared for the analysis of volatile constituents from a traditional Chinese medicine (TCM) of the dried ripe fruit of Fructus Amomi (Sha Ren). A total of 38 compounds were identified by gas chromatography/mass spectrometry. Different SFE and SPME parameters (modifier content, extraction pressure, and temperature for SFE and fibers, extraction temperature, and time for SPME) were studied. The results by SFE and SPME were compared with those obtained by conventional SD and SE methods. The results showed that SFE and SPME are better sample preparation techniques than SD and SE. Due to SFE's requirement for expensive specialized instrumentation, the simplicity, low cost, and speed of SPME make it a more appropriate technique for extraction of volatile constituents in TCMs.

Optimization of preconcentration and isolation for the determination of 15 phenols by supercritical-fluid extraction and gas chromatography with metallomesogenic stationary phase

Based on the merits of well-established capillary gas chromatography (GC), metallomesogenic polymer was used as the stationary phase and flame ionization detector (FID) was used as the detector, the analysis of phenolic compounds explored the possibility of application in complex matrices. We proposed the method combined supercritical-fluid extraction (SFE) of phenolic compounds, which had been enriched on the solid supports of XAD-4 resins, and then with their determinations by capillary GC-FID. The SFE parameters suitable for 15 phenols simultaneously adsorbed onto XAD-4 resins in aqueous solution were assessed by a 4 5 factorial design method. The best results were 5 min static time, 10 min dynamic time, 0.25 ml methanol spiked, 80 °C oven temperature and 410 atm CO 2 pressure. Also, other parametric conditions for specific phenols were revealed and analyzed. In the comparison with Soxhlet extraction with regard to the recoveries and reproducibility, the developed SFE was quite superior and helped to reduce the detection limit of aqueous samples to 10 −2-fold. Eventually, the polluted soils near a pharmaceutical factory were primarily tested and given the probable distribution.

Chelating resin sorption followed by supercritical fluid extraction and liquid chromatographic determination of aluminum in liquid samples

To determine aluminum content in liquid samples, a method combining the techniques of chelating resin sorption and supercritical fluid extraction (SFE) was described. The chelating resin highly selective for aluminum at pH <3 was prepared by impregnating Chromazural S (CAS) on Amberlite IRA-400. The sorbed aluminum was extracted with supercritical CO 2 containing trifluoroacetylacetone (TFA). A 4 5 factorial design was conducted for the simultaneous determination of various analytical SFE parameters including temperature, pressure, CO 2 density, extraction time, and fluid flow rate. After removing excess TFA with NaOH (0.1 M), the extract was analyzed by HPLC with UV detection at 296 nm. We also demonstrated that the interference from iron complex in the applied liquid sample was negligible in this procedure. The aluminum content in Oolong tea determined by our method, 1.46 and 1.10 ppm in the first and second infusion, respectively, was successfully verified by spectrophotometry. The established method was also applied to determine the aluminum content in beer, Coca Cola, and orange juice.

Optimization of parameters for the supercritical fluid extraction in the determination of N-nitrosamines in rubbers

The study of the possibilities of supercritical fluid extraction (SFE) with N-nitrosamines in rubbers has been carried out. Home-made materials fortified with several N-nitrosamines were prepared in order to optimize the SFE parameters. A Plackett–Burman design was employed to evaluate the influence of those parameters to be controlled in SFE, such as pressure, temperature, static and dynamic time, restrictor temperature and volume of modifier while CO 2 was used as the extraction fluid. An extra central composite design for the main factors (according to the previously obtained results) was also developed in order to refine the best supercritical conditions for the extraction of N-nitrosamines from rubbers. Gas chromatography with a nitrogen and phosphorus sensitive detector was used to achieve sensitivity and limits of detection for the concentrations expected in plastic materials. The proposed analytical method has shown to be useful in the determination of N-nitrosamines even for complex matrices.

The use of immobilized Candida antarctica lipase for simultaneous supercritical fluid extraction and in‐situ methanolysis of cis‐vaccenic acid in milkweed seeds

Abstractcis‐Vaccenate was determined in milkweed (Ascelpias) seed employing supercritical fluid extraction (SFE) with in‐situ enzymatic methanolysis. Candida antarctica lipase type B immobilized onto two different types of carrier materials—a hydrophobic polymer (Novozyme 435) and a silica‐based material (NovoSample 40013)—was investigated. Several SFE parameters were investigated to find the optimal conditions, including extraction time, temperature, methanol concentration, and water level. It was shown that 90 min of dynamic extraction/reaction time was required, and that the optimal methanol and water concentrations differed for the two enzyme preparations studied. Overall, Novozyme 435 demonstrated the fastest reaction kinetics and consistently gave the highest vaccenate yields. The optimized methodology was applied on 15 species of milkweed seeds, giving an average recovery of 105±7% when compared to results obtained using a conventional methodology. The average relative standard deviations were 8% for the enzyme‐based method and 4% for the reference method. The proposed methodology was faster, was less laborious, and consumed less organic solvent than the reference method. Hence, SFE with in‐situ enzymatic methanolysis is a promising methodology for the analysis of FA in oilseeds.

Application of central composite designs in the supercritical fluid extraction of tropane alkaloids in plant extracts

Central composite designs were used in the study of supercritical fluid extraction (SFE) of three tropane alkaloids : hyoscyamine and scopolamine from Datura candida x D. aurea hairy roots and cocaine from coca leaves (Erythroxylum coca). Several SFE parameters, such as pressure, temperature, the nature and percentage of the polar modifier were examined. The tropane alkaloid extraction yield was established as response. A comparison between the predicted and the experimental extraction yields was established in order to assess the prediction quality of the model. Response surfaces were drawn from the mathematical models and enabled to determine the optimal conditions and to visualise the method robustness. The behaviour of the compounds investigated was discussed in relation with the selected SFE parameters.

Comparison of solid-phase extraction and supercritical fluid extraction for extraction of polycyclic aromatic hydrocarbons from drinking water

This work compares four different extraction techniques [solid-phase extraction (SPE), supercritical fluid extraction (SFE), solid-phase extraction followed by supercritical fluid extraction (SPE/SFE), and liquid–liquid extraction (LLE)] for the extraction of 16 polycyclic aromatic hydrocarbons (PAHs) from both fortified and drinking water. For SPE, the analytes were trapped on three different solid phases (octadecyl, cyanopropyl, and phenyl) and eluted with methylene chloride or acetonitrile. The SFE parameters were optimized by introducing the spiked water directly into the extraction cell and extracting with CO2 modified with methylene chloride. These studies showed that for SPE, the octadecyl phase had the best recoveries for volatile PAHs, and methylene chloride was the better solvent. SPE/SFE had good recoveries for all compounds; SFE had less steps, less exposure to solvents, and less extraction time when placing the matrix directly into the extraction cell; however, recovery was less than SPE/SFE. LLE had the worst reproducibility and recovery. © 1998 John Wiley & Sons, Inc. J Micro Sep 10: 125–131, 1998

Effect of Extraction Conditions and Modifiers on the Supercritical Fluid Extraction of 88 Pesticides

Supercritical fluid extraction (SFE) conditions for multiresidue analysis of pesticides are evaluated using diatomaceous earth (Celite) spiked with 88 pesticides (16 organochlorine, 33 organophosphorus, 8 pyrethroid, 12 carbamate, and 19 other pesticides). The SFE parameters considered are CO2 density, CO2 flow rate, extraction temperature, static and dynamic extraction times, trap temperature, and addition of modifier. SFE without modifier is insufficient to extract polar pesticides from fortified Celite. The addition of water to Celite is most effective in effective modifier, but the recovery of captafol, captan, phosmet, and chinomethionat decreases as time goes on after the addition of methanol. The best obtained conditions of SFE (2.0 g sample) are as follows: 0.40 mL of water as a modifier, 0.70 g/mL CO2 density, 50°C extraction temperature, 2.0 mL/min CO2 flow rate, 3.0 min of static extraction, and 20.0 min of dynamic extraction. The extracted pesticides are collected on an octadecylsilane trap at 30°C. Quantitative analysis of the 88 pesticides is performed by gas chromatography—mass spectrometry using the selected ion monitoring mode. Recoveries from fortified Celite are greater than 90% for 79 pesticides and greater than 70% for the other pesticides, except acephate, methamidophos, and propamocarb. The relative standard deviations of the recoveries are less than 5% for almost all of the pesticides.

Development of a supercritical fluid extraction method for determination of lipid classes and total fat in meats and its comparison with conventional methods

A method has been developed for the determination of total fat and lipid classes in meat using supercritical fluid extraction (SFE). The results agreed well with results from the conventional Bligh and Dyer and Schmid, Bondzynski and Ratzlaff extraction methods. SFE has advantages compared to the latter methods of a low consumption of hazardous organic solvents and shorter extraction time. After investigation of several different conditions, the most rapid extraction was achieved by adding 1 ml of cyclohexane to a 0.5-g sample mixed with 1 g Hydromatrix in a 7-ml thimble. The optimized SFE parameters were: 370 bar, 50°C, 8% ethanol modifier, 4 ml/min dynamic flow for 30 min and collection with a tube leading to a vial.

Study of the Effects of Environmental Variables and Supercritical Fluid Extraction Parameters on the Extractability of Pesticide Residues from Soils Using a Multivariate Optimization Scheme

A multivariate optimization scheme (MOS) was used to investigate the effects of environmental variables and supercritical fluid extraction (SFE) parameters on the extractability of pesticide residues from soil samples. MOS is a highly efficient technique for studying a large number of variables and identifying optimal extraction conditions. MOS offered the opportunity to systematically and simultaneously examine the interaction and effect profiles among important soil variables and extraction parameters. Pesticide residence time in soil had a major influence on binding extent for all tested pesticides. Extractability as a function of soil composition was greatly dependent on the particular pesticide examined. Bensulfuron-methyl was the most difficult to extract from soils containing high levels of both organic matter and clay. Atrazine was extracted more easily than diuron. High organic matter and high clay content led to strong binding for diuron and atrazine, respectively. Effects of SFE parameters on e...

Supercritical Fluid Extraction from Soil and HPLC Analysis of Cyanazine Herbicide

Efficacy of supercritical fluid extraction (SFE) for the recovery of cyanazine (2-[[4-chloro-6-(ethylamino)-1,3,5-triazin-2-yl]amino]-2-methylpropionitrile) from soil was investigated. A reverse-phase HPLC method and a TLC method were developed for quantitative separation of cyanazine from its seven metabolites. Dundee silty clay loam soil treated with 14C-ring-labeled and nonlabeled cyanazine was used. Several SFE parameters were optimized for maximum recovery of cyanazine. Methanol/water (1:1) added directly to the soil matrix was the most efficient modifier. Extraction with supercritical CO2 at a flow rate of 3.0 mL min-1, a density of 0.90 g mL-1, and an extraction temperature of 50 °C was optimal. With 6 and 20 min static and dynamic extraction times, respectively, cyanazine could be extracted from soil in 40−45 min. With a considerable savings in time and lower waste solvent generation, recoveries (>90%) very similar to conventional extraction procedures could be obtained. Extraction of some of the cyanazine metabolites from soil, under the conditions optimized for cyanazine, was also investigated. Keywords: SFE; cyanazine; metabolites; HPLC; TLC

Optimization of a drying method for filtered suspended solids from natural waters for supercritical fluid extraction analysis of hydrophobic organic compounds

This paper describes a closed-jar drying method (with a desiccant), developed specifically for filtered suspended solids, as a more efficient alternative to air-drying or freeze-drying. Supercritical fluid extraction (SFE) recovery studies to evaluate its efficiency were achieved with hydrophobic organic compounds of log K ow ranging from 3.9 to 5.2, represented by polynuclear aromatic hydrocarbons (PAHs). The PAH analytes were “loaded” onto the suspended solids by sorption to better represent field-collected material. The necessity of drying a sample of filtered suspended solids prior to SFE was confirmed by direct comparison of the SFE recoveries from dry and wet samples. These results indicate that the drying technique is needed to develop reproducible samples to analyze by SFE. An explanation for the effect of water in SFE is proposed. Optimization of SFE parameters for natural filtered suspended solids confirms that the best conditions for SFE of PAHs consist of a pressure of 355 atm, a temperature of 120 °C and a modifier consisting of 750 μl of a 1:1:1 (v/v) mixture of water, methanol and methylene chloride.

Application of Supercritical Fluid Extraction and High Performance Liquid Chromatography/Mass Spectrometry for the Determination of Some Anabolic Agents Directly from Bovine Tissue Samples

Abstract The aim of the present work was to evaluate the feasibility of supercritical fluid extraction (SFE) of some growth-promoting anabolic steroids directly from bovine tissue samples with carbon dioxide as a supercritical fluid. The study was divided into two phases. The first phase involved the optimization of SFE parameters versus recovery and repeatability. Results were obtained by high performance liquid chromatography (HPLC) or supercritical fluid chromatography (SFC). The second set of studies consisted of SFE from the real samples monitored by the combination of high performance liquid chromatography atmospheric pressure chemical ionization mass spectrometry (HPLC/APCIMS). The limit of detection was about 10 ppb, but 100 ppb is the practical detection limit for SFE-HPLC/MS analysis under the experimental conditions used in this study. The results from this work suggested that SFE may be useful for isolation of target compounds from complex biological samples.

Supercritical fluid extraction-liquid chromatography method development for a polymeric controlled-release drug formulation

We have recently been involved in the development of a method for assaying the active component in a controlled-release drug formulation, which is composed of a drug substance covalently bonded to polymer matrix. The drug substance in the formulation is the active enantiomer of misoprostol, a synthetic analog of natural prostaglandins and the active ingredient in Cytotec ®. Our method development consisted of a systematic evaluation of dynamic, off-line supercritical fluid extraction (SFE) as sample preparation for the formulation assay. Extracts were analyzed with normal phase and reversed-phase HPLC methods. The reversed-phase system utilized postcolumn reaction to provide selective detection of the extracted prostaglandin sample components. Several SFE parameters were investigated to optimize the recovery of the drug substance from the formulation, including sample quantity, extraction cell volume, extraction duration, supercritical carbon dioxide modifier, temperature, pressure, and collection solvent. The SFE experiments were completed with a commercially available multicell extractor. Preliminary validation studies utilized a formulation made with radiolabeled drug to determine the recovery achieved under the optimized SFE conditions and assessed the precision of replicate determinations. Analysis was completed under the optimized conditions to quantitate levels of the active component and related compounds in lots of the experimental polymeric formulation and to determine the total weight per cent extracted.

Evaluation of a Supercritical Fluid Extraction Method for Hexachlorobenzene from Artificially Spiked and Naturally Contaminated Oil Seeds and Soil Samples

Abstract Great differences in the supercritical fluid extraction (SFE) yield of hexachlorobenzene (HCB) in artificially spiked and naturally contaminated soil samples have been found. Extraction methods optimized for organochlorine pesticides (OCP's) in spiked samples yielding 98% recovery for HCB, failed in terms of sufficient recovery from real samples. The extraction yield dropped to 50% for HCB and, consequently, resulted in an unacceptable high variance of the results obtained (R.S.D. > 10%). Therefore, a procedure for the optimization of SFE parameters including carbon dioxide (CO2) density, extraction temperature and addition of organic modifiers for reliable HCB determination in real samples is reported. A nearly complete recovery of HCB (98%) was obtained for 0.80 g/ml CO2, 80[ddot]C, 15 min and the addition of 5% methanol. Direct injection of SFE-extracts from soil into GC-ECD could be achieved after selectively trapping the analytes on minicolumns filled with C18 coated silica material and elut...