Simultaneous measurement of fluoroquinolones in eggs by a combination of supercritical fluid extraction and high pressure liquid chromatography

Simultaneous detection of the fluoroquinolone antibiotics ciprofloxacin, enrofloxacin, ofloxacin, and norfloxacin in eggs by a combination of supercritical fluid extraction (SFE) and high pressure liquid chromatography (HPLC) was studied. Lipid matrices that have been considered to result in poor extraction and isolation of fluoroquinolones in eggs were removed first by SFE with supercritical CO(2) alone, and then the fluoroquinolones were extracted by SFE with supercritical CO(2) containing 20% (v/v) methanol for HPLC analysis. A time-course study of the extraction of lipid matrices of eggs suggested that the SFE method successfully removed the matrices within 20 min. When the fluoroquinolones added to control eggs were extracted by SFE, the extraction efficiency was similar to that by the solvent extraction method, giving the recovery percentages from 83 to 96% in a 40 min-extraction time. The fluoroquinolones extracted from eggs by SFE were analyzed simultaneously by HPLC equipped with a fluorescence detector with detection sensitivity at about 10 ppb for the detection limit. The standard calibration profiles of fluoroquinolones showed linear responses to HPLC, showing more than 0.995 for the mean r(2) value. This is the first report of the simultaneous measurement of fluoroquinolones in eggs by a combination of SFE and HPLC. Using the SFE method allowed us to avoid extensive sample preparation such as solvent extraction and chromatographic cleanup that are basically required in extraction of fluoroquinolones.     

Simultaneous Measurement of Fluoroquinolones in Eggs by a Combination of Supercritical Fluid Extraction and High Pressure Liquid Chromatography

Simultaneous detection of the fluoroquinolone antibiotics ciprofloxacin, enrofloxacin, ofloxacin, and norfloxacin in eggs by a combination of supercritical fluid extraction (SFE) and high pressure liquid chromatography (HPLC) was studied. Lipid matrices that have been considered to result in poor extraction and isolation of fluoroquinolones in eggs were removed first by SFE with supercritical CO₂ alone, and then the fluoroquinolones were extracted by SFE with supercritical CO₂ containing 20% (v/v) methanol for HPLC analysis. A time-course study of the extraction of lipid matrices of eggs suggested that the SFE method successfully removed the matrices within 20 min. When the fluoroquinolones added to control eggs were extracted by SFE, the extraction efficiency was similar to that by the solvent extraction method, giving the recovery percentages from 83 to 96% in a 40 min-extraction time. The fluoroquinolones extracted from eggs by SFE were analyzed simultaneously by HPLC equipped with a fluorescence detector with detection sensitivity at about 10 ppb for the detection limit. The standard calibration profiles of fluoroquinolones showed linear responses to HPLC, showing more than 0.995 for the mean r ² value. This is the first report of the simultaneous measurement of fluoroquinolones in eggs by a combination of SFE and HPLC. Using the SFE method allowed us to avoid extensive sample preparation such as solvent extraction and chromatographic cleanup that are basically required in extraction of fluoroquinolones.     

Antileishmanial activity of fucosterol recovered from Lessonia vadosa Searles (Lessoniaceae) by SFE,PSE and CPC

Fucosterol, a triterpene derivative encountered in several alga species, provides a wide range of biological activities, such as protection against metabolic syndrome, or against UV-induced skin damage. We describe here the comparison of extraction by supercritical fluid (SFE) and pressurized solvent (PSE) of the brown alga Lessonia vadosa mainly abundant in the coastal water of Patagonia, followed by the isolation of fucosterol, using centrifugal partition chromatography (CPC), in association with HPLC–UV quantification. After collection, the seaweed was dried, ground and extracted either by PSE or by SFE under various conditions. The yield and the content in fucosterol of each extract were determined by HPLC–UV. Optimization of a biphasic solvent system and K_D calculation led to the isolation of pure fucosterol with high recovery rate. Extraction by SFE using CO₂ at 180 bar and 50 °C with 20 to 30 % of cellulose as modifier and CPC purification by cyclohexane/acetone/methanol/water 10/1/10/1 with lower layer as mobile phase led to the best results in terms of yield, purity, time and solvent consumption. Natural and semisynthetic steroid derivatives have been previously shown to be potential drug candidates against parasitic diseases including leishmaniasis. In this context fucosterol was evaluated and demonstrated noticeable antileishmanial activity (IC₅₀ < 10 μM) against intracellular amastigotes with limited or no cytotoxicity in host cell macrophages. These results make this compound a valuable starting scaffold for pharmacomodulation. Adaptation of the procedure by slight modifications of the extraction and/or isolation conditions could permit the exploitation of other alga species as raw material. Since SFE and CPC are available for pilot and batch production, this work may serve as a model for further scale-up and industrial development.     

超临界流体萃取——高效液相色谱法测定百合中秋水仙碱

分别用超临界二氧化碳流体和有机溶剂萃取百合中的秋水仙碱,然后用高效液相色谱法直接测定萃取物中秋水仙碱的含量,从而测得百合中秋水仙碱的含量。超临界流体萃取的条件是：用乙醇作提携剂,萃取压力为18MPa,萃取温度为40℃,高效液相色谱测定条件为：ODS柱,甲醇：磷酸二氢钾溶液作流动相,检测波长为220nm,此法快速,简便,准确,可应用于秋水仙碱原料,制剂及其它植物中秋水仙碱含量的测定。     

Experimental design in supercritical fluid extraction of cocaine from coca leaves

An optimisation procedure for the supercritical fluid extraction (SFE) of cocaine from the leaves of Erythroxylum coca var. coca was investigated by means of experimental design. After preliminary experiments where the SFE rate-controlling mechanism was determined, a central composite design was applied to evaluate interactions between selected SFE factors such as pressure, temperature, nature and percentage of the polar modifier, as well as to optimise these factors. Predicted and experimental contents of cocaine were compared and robustness of the extraction method estimated by drawing response surfaces. The analysis of cocaine in crude extracts was carried out by capillary GC equipped with a flame ionisation detector (GC-FID), as well as by capillary GC coupled with a mass spectrometer (GC-MS) for peak identification.     

HPLC comparison of supercritical fluid extraction and solvent extraction of coumarins from the peel of Citrus maxima fruit

The efficiency of carbon dioxide supercritical fluid extraction (SFE) of the biologically active compounds imperatorin, meranzin and meranzin hydrate from the fruit peel of Citrus maxima Merr. has been compared with that of solvent extraction with acetone. Under the best SFE conditions tested for the three coumarins, which involved extraction at 50 degrees C and 27.6 MPa, the extractive efficiencies were 84, 76 and 18% for imperatorin, meranzin and meranzin hydrate, respectively. The presence of modifiers significantly affected the extraction efficiency: the highest extraction efficiency of the three coumarins was obtained with ethanol as modifier.     

川芎及土壤中毒死蜱残留检测提取方法

为建立川芎植株和土壤中农药毒死蜱残留检测的最佳提取方法,利用气相色谱-质谱法测定毒死蜱残留量,并采用正交设计,考察提取溶剂、提取时间、提取次数和溶剂量对农药毒死蜱回收率的影响,优选提取方法。川芎地上部分和根茎中毒死蜱残留的最佳提取方法为：乙腈3倍量超声提取2次,每次15 min。土壤中毒死蜱残留的最佳提取方法为：乙酸乙酯10倍量震荡提取2次,每次30 min。经方法学验证,筛选建立的提取方法均达到农药残留分析要求,该方法可行。     

超临界CO_2萃取冬虫夏草子座挥发性成分的GC-MS研究

报道冬虫夏草挥发性成分的组成,为其进一步的研究工作奠定基础。采用超临界CO2萃取法从冬虫夏草子座中提取挥发性成分,气相色谱-质谱联用技术对其化学成分进行分析。超临界流体萃取物共鉴定了39种组分,占总馏出组分的86.6%以上,占色谱总馏出峰面积的98.56%以上。已鉴定组分中,含量最高的为油酸,相对含量25.6%;其次为亚油酸,相对含量22.67%;再次为棕榈酸11.86%。超临界CO2萃取法能更真实、全面的反映药材中的化学成分,适合于珍稀中药材相关组分的测定。     

Supercritical-fluid extraction of synthetic pyrethroids from wool

A stepwise approach was used to develop a supercritical fluid extraction (SFE) method for analysis of synthetic pyrethroids (SPs) on a wool matrix, commencing with a simple inert matrix to examine the solubility of the pyrethroids in the extraction fluid CO(2) and then extended to the real wool matrix. Chemometric approaches were used to determine the SFE optimum conditions. It was found that pyrethroids were readily extractable from an inert matrix over a wide range of pressure (170-350 atm) and at low temperature (<90 degrees C). Subambient hexane efficiently trapped the compounds from the depressurised fluid. Excessively high pressure and temperature resulted in poor trapping, isomerisation and possibly degradation of some components. With spiked wool samples method modifications focused on reducing the coextraction of grease, a bulk matrix component of raw wool. By using alumina (containing 8% moisture) and operating the extraction at 50 degrees C, 200 atm for 60 min, sufficiently clean extracts of pyrethroids suitable for gas chromatography-electron-capture detection analysis were obtained. The recoveries of all SPs were satisfactory (78-101%) over the range of 0.5-5 microg/g levels of these compounds. The precision of the entire analysis procedure was comparable to the conventional Soxhlet extraction method. Detection limits of some commonly used SPs for sheep treatment were also evaluated. Comparable results relative to those achieved by solvent extraction for incurred wool samples were obtained with a recovery of 81-85%. The results, however, suffered high uncertainties (R.S.D. approximately 19-24%) due to the small amount of wool sample taken in each extraction and the suspected inhomogeneity of the wool. Different persistences of cypermethrin isomers in wool were observed.     

Analysis of the sulfomycin component of alexomycin in animal feed by enhanced solvent extraction and supercritical fluid chromatography

Enhanced solvent extraction (ESE) was used to isolate components of alexomycin from different types of animal feed samples. It was demonstrated that ESE was more economical as regards money and, for this particular matrix, twice as fast as supercritical fluid extraction (SFE) even though it was demonstrated that alexomycin can be extracted from feed quantitatively using both ESE and SFE. Supercritical fluid chromatography was used to separate alexomycin from other co-extractives of feed since liquid chromatography was unable to isolate the alexomycin for quantification purposes. Our results also showed that the concentration of alexomycin in an extruded sample was approximately half of the concentration which was originally added to the feed.     

超临界CO_2和微波辅助萃取艾叶挥发油工艺的研究

通过超临界CO2萃取均匀设计实验和微波辅助萃取艾叶挥发油的正交实验比较,考察影响提取的主要因素,寻求最佳萃取工艺。超临界CO2萃取最佳工艺条件为:萃取压力16MP,萃取温度31℃,CO2流量20kg/h和时间80min,得率3.75%;微波萃取最佳工艺条件为:辐射功率720w,辐射时间200s,溶剂量400mL,洗涤剂量50mL,得率4.85%。水蒸馏法提取率为1.87%。结果表明超临界CO2和水蒸馏法萃取艾叶挥发油品质最好;微波萃取收率最高,但品质较差。     

Fate of 14C-labeled anthracene and hexadecane in compost-manured soil

Experiments were carried out to evaluate the impact of the addition of ripe compost on the degradation of two ¹⁴C-labeled hydrocarbon model compounds (anthracene and hexadecane) in soil. The addition of mature compost (20 % dry wt./dry wt.) stimulated significantly the disappearance of the extractable fraction of both compounds. With compost, 23 % of the labeled anthracene was transformed into ¹⁴CO₂ and 42 % was fixed to the soil matrix irreversibly. In the unsupplemented control reactor more than 88 % of the original anthracene could be recovered by either of two applied organic extraction procedures. The formation of non-extractable bound residues was less significant with [¹⁴C] hexadecane since only 21 % of the labeled carbon had become non-extractable after 103 days. The results presented show that compost could stimulate the depletion of hydrocarbons by either mineralization or the formation of unextractable bound residues (humification). The latter process might be a significant route of depletion in soil especially, for those hydrocarbons that are mineralized only slowly. The meaning of this finding for the assessment of soil bioremediation is discussed.These authors contributed equally to the presented work and should therefore both be considered as first authors     

超临界二氧化碳萃取亚麻籽油的研究

采用半连续流程以亚麻籽（含水率5％,含油率47％）为原料,超临界CO2为溶剂萃取亚麻籽油。探讨了操作压力,温度,时间,CO2流量及亚麻籽破碎情况对萃取的影响。用国家标准分析了不同萃取条件下得到的亚麻籽油,用GC－MS分析了亚麻籽油的组成,亚麻酸是主要成分,超临界萃取得到的亚麻籽油可作为高质量的保健食用油。     

Combining supercritical fluid extraction of soil herbicides with enzyme immunoassay analysis

Supercritical fluid extraction (SFE) of soil herbicides followed by enzyme immunoassay analysis (EIA) is explained in a step-by-step process. Extracted herbicides, include 2,4-D, simazine, atrazine, and alachlor. The herbicide, trifluralin was not successfully analyzed by EIA because of crossreacting metabolites. Problems with SFE, including uneven packing of cells, leaks, uneven flow and clogging, can largely be eliminated as the method parameters are optimized. It was necessary to add modifiers including methanol or acetone to the SF CO₂ to increase the solubility of the analytes. Detection limits of 2.5 ng/g soil for atrazine and alachlor and 15 ng/g soil for simazine and 2,4-D without concentration of the sample were achieved. Recoveries above 80% and relative standard deviations (RSDs) less than 15% for 2,4-D simazine, atrazine and alachlor were achieved. Atrazine and alachlor recoveries were above 90% with RSDs below 10%. Forty soil samples could be extracted and analyzed in an 8-h day.     

北细辛超临界萃取物挥发性成分的GC-MS分析

采用超临界流体萃取法(SFE)和水蒸气蒸馏法分别对北细辛根及根茎进行提取分离,分别得5.5%SFE萃取物和2.8%挥发油。应用GC-MS分析,从北细辛SFE萃取物中鉴定出7种化学成分,占萃取物总量的72.70%,其中甲基丁香酚为44.62%;从细辛挥发油中鉴定出19种化学成分,占挥发油总量的88.53%,其中甲基丁香酚为43.02%。两种方法有6种成分完全相同,其中致癌物质黄樟油素SFE法比蒸馏法低2.8倍。北细辛根及根茎超临界萃取物与水蒸汽蒸馏挥发油主要成分相同,但其化学组成存在较大差异,提示药效亦不相同。超临界流体萃取法是剂型改革的有效方法之一。     

Isolation of chlorophylls and carotenoids from freshwater algae using different extraction methods

Usually marine algae are an excellent source of pigments for different commercial sectors. Freshwater macroalgae can be exploited as a good source of biologically active compounds provided an appropriate extraction method is developed. The efficiency of four methods, like microwave‐assisted (MAE), ultrasound‐assisted extraction (UAE), supercritical fluid extraction (SFE) with ethanol as a co‐solvent, as well as conventional Soxhlet extraction were studied in the same conditions (time, solvent and temperature) for the recovery of chlorophylls and carotenoids from three freshwater green algae species: Cladophora glomerata, Cladophora rivularis and Ulva flexuosa. UV‐Vis spectrophotometry was used to determine chlorophyll a, chlorophyll b and total carotenoid content in obtained extracts. The results of this study showed that the advantages of novel extraction techniques (MAE and UAE) include higher yield and, in consequence, lower costs compared to traditional solvent extraction techniques. These methods were much more efficient in freshwater green algae pigment recovery than the classic Soxhlet extraction as well as SFE.     

Supercritical extraction and supercritical antisolvent fractionation of natural products from plant material: comparative results on Persea indica

Supercritical fluids (SCFs) are alternative solvents in the field of Green Chemistry that are being developed as advanced separation techniques due to their combined properties such as the penetrability of a gas and the solvent power of a liquid. These characteristics are used in the supercritical fluid extraction (SFE), where compounds of interest can be extracted after mixing a SCF as a solvent with a matrix in a pressurized vessel. Supercritical antisolvent fractionation (SAF) uses the SCF as antisolvent, allowing for the precipitation of insoluble compounds in the SCF-organic solution mixture. An updated overview of SFE and SAF of natural products is presented in this article. Additionally we compare the results of SFE, SAF and organic soxhlet extraction (OSE) of Persea indica, a Macaronesian paleoendemism with strong insecticidal components. The composition of the extracts was analyzed by HPLC-MS, showing in the SFE extracts as major components ryanodol, cinnzeylanol and alkyl-γ-lactones, with their abundance varying with the extraction conditions. On the other hand, the SAF allowed for the fractionation of a liquid solution to give a ryanodol enriched extract (31 % more ryanodol than the initial ethanolic solution). The antifeedant and postingestive effects of these extracts on Spodoptera littoralis showed that the SAF extracts were the most active followed by SFE and OSE and their different effects can be partially explained by their composition.     

Supercritical fluid extraction of naringin from the peel of Citrus paradisi

The highest yield (14.4 g/kg) of naringin, the major flavonoid from the peel of Citrus paradisi L., that could be achieved by supercritical fluid extraction was obtained using supercritical carbon dioxide modified with 15% ethanol and fresh (rather than dried) peels at 95 bar and 58.6 degrees C. This yield is higher than that attained by the conventional technique of maceration, and close to those obtained by reflux and Soxhlet methods. Furthermore, supercritical fluid extraction consumes less solvent and provides a shorter extraction time than conventional extraction methods.     

Butanol recovery from fermentations by liquid-liquid extraction and membrane solvent extraction

Extraction can successfully be used for in-situ alcohol recovery in butanol fermentations to increase the substrate conversion. An advantage of extraction over other recovery methods may be the high capacity of the solvent and the high selectivity of the alcohol/water separation. Extraction, however, is a comprehensive operation, and the design of an extraction apparatus can be complex. The aim of this study is to assess the practical applicability of liquid-liquid extraction and membrane solvent extraction in butanol fermentations. In this view various aspects of extraction processes were investigated.Thirty-six chemicals were tested for the distribution coefficient for butanol, the selectivity of alcohol/water separation and the toxicity towards Clostridia. Convenient extractants were found in the group of esters with high molar mass.Liquid-liquid extraction was carried out in a stirred fermenter and a spray column. The formation of emulsions and the fouling of the solvent in a fermentation broth causes problems with the operation of this type of equipment. With membrane solvent extraction, in which the solvent is separated from the broth by a membrane, a dispersion-free extraction is possible, leading to an easy operation of the equipment. In this case the mass transfer in the membrane becomes important.With membrane solvent extraction the development of a process is emphasized in which the extraction characteristics of the solvent are combined with the property of silicone rubber membranes to separate butanol from water. In the case of apolar solvents with a high molar mass, the characteristics of the membrane process are determined completely by the solvent. In the case of polar solvents (e.g. ethylene glycol), the permselectivity of the membrane can profitably be used. This concept leads to a novel type of extraction process in which alcohol is extracted with a water-soluble solvent via a hydrophobic semipermeable membrane. This extraction process has been investigated for the recovery of butanol and ethanol from water. A major drawback in all processes with membrane solvent extraction was the permeation of part of the solvent to the aqueous phase.The extraction processes were coupled to batch, fed batch and continuous butanol fermentations to affirm the applicability of the recovery techniques in the actual process. In the batch and fed batch fermentations a three-fold increase in the substrate consumption could be achieved, in the continuous fermentation about 30% increase.     

Determination of food constituents based on SFE: applications to vitamins A and E in meat and milk

A method has been developed for the determination of vitamins A and E in food using supercritical fluid extraction (SFE), applying liquid or solid trapping, with an accuracy equal to conventional solvent extraction methods. Under optimal conditions, using methanol modified carbon dioxide as a supercritical fluid, Hydromatrix as a water adsorbent, and with a small amount of ascorbic acid and methanol added to the sample, the extraction time is reduced to 80 min. This time is considerably shorter than in conventional methods. Other advantages are the reduction of manual manipulations leading to lower labour costs and reduced consumption of organic solvents in the sample preparation step.