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1.
Chu K  Xu W  Li H  Chen L  Zhang Y  Tang X 《Molecules (Basel, Switzerland)》2011,16(12):10029-10045
The supercritical fluid extraction (SFE) of Lepidium apetalum seed oil and its anti-oxidant activity were studied. The SFE process was optimized using response surface methodology (RSM) with a central composite design (CCD). Independent variables, namely operating pressure, temperature, time and flow rate were evaluated. The maximum extraction of Lepidium apetalum seed oil by SFE-CO? (about 36.3%) was obtained when SFE-CO? extraction was carried out under the optimal conditions of 30.0 MPa of pressure, 70 °C of temperature, 120 min of extraction time and 25.95 L/h of flow rate. GC-MS analysis showed the presence of four fatty acids in Lepidium apetalum seed oil, with a high content (91.0%) of unsaturated fatty acid. The anti-oxidant activity of the oil was assessed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assay and 2,2'-azino- bis(3-ethylbenzthiazoline-6-sulphonic acid) diammonium salt (ABTS) test. Lepidium apetalum seed oil possessed a notable concentration-dependent antioxidant activity, with IC?? values of 1.00 and 3.75 mg/mL, respectively.  相似文献   

2.
Wang W  Meng B  Lu X  Liu Y  Tao S 《Analytica chimica acta》2007,602(2):211-222
The methods of simultaneous extraction of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) from soils using Soxhlet extraction, microwave-assisted extraction (MAE) and accelerated solvent extraction (ASE) were established, and the extraction efficiencies using the three methods were systemically compared from procedural blank, limits of detection and quantification, method recovery and reproducibility, method chromatogram and other factors. In addition, soils with different total organic carbon contents were used to test the extraction efficiencies of the three methods. The results showed that the values obtained in this study were comparable with the values reported by other studies. In some respects such as method recovery and reproducibility, there were no significant differences among the three methods for the extraction of PAHs and OCPs. In some respects such as procedural blank and limits of detection and quantification, there were significant differences among the three methods. Overall, ASE had the best extraction efficiency compared to MAE and Soxhlet extraction, and the extraction efficiencies of MAE and Soxhlet extraction were comparable to each other depending on the property such as TOC content of the studied soil. Considering other factors such as solvent consumption and extraction time, ASE and MAE are preferable to Soxhlet extraction.  相似文献   

3.
The application of a new focused microwave-assisted Soxhlet extractor for the extraction of polychlorinated biphenyls from differently aged soils is here presented. The new extractor overcomes the disadvantages of previous devices based on the same principle and enables a fully automated extraction of two samples simultaneously. The variables affecting the extraction step (namely, power of irradiation, irradiation time, extractant volume, extractant composition and number of extraction cycles) have been optimized using experimental design methodology. The optimized method has also been applied to a certified reference material (CRM910-050 "real" contaminated soil) for quality assurance validation. Quantification of the target compounds has been performed by GC with ion-trap MS. The mass spectrometer was operated in the electron-ionization mode, with selected-ion monitoring at m/z 152, 186, 292, 326 and 498. The results obtained have demonstrated that this approach is as efficient as conventional Soxhlet but with a drastic reduction of both extraction time (70 min vs. 24 h for the "real" contaminated soil) and organic solvent disposal, as 75-80% of the extractant is recycled.  相似文献   

4.
Traditional hydrodistillation (HD), supercritical fluid extraction (SFE), organic solvent extraction (SE), and water microwave assisted hydrodistillation (MAHD) techniques were compared and evaluated for their effectiveness in the isolation of rosemary essential oil. The microwave assisted hydrodistillation technique was optimized in terms of both delivered power and time duration. The extracts/distillates were analyzed by GC and GC-MS. Microwave distillation, which exploits the physical action of microwaves on plants, showed a series of advantages over the other approaches: low cost, use of water in sample pre-treatment step, greatly reduced isolation time, and attainment of high quality essential oil distillate. Moreover, the absence of environmental impact of this innovative technique was also emphasized.  相似文献   

5.
A shotgun proteomics approach was used to characterize the quinoa seed proteome. To obtain comprehensive proteomic data from quinoa seeds three different precipitation procedures were employed: MeOH/CHCl3/double‐distilled H2O, acetone either alone or with trichloroacetic acid; the isolated proteins were then in‐solution digested and the resulting peptides were analyzed by nano‐liquid chromatography coupled to tandem mass spectrometry. However, since quinoa is a nonmodel plant species, only a few protein sequences are included in the most widely known protein sequence databases. To improve the data reliability a UniProt subdatabase, containing only proteins of Caryophillales order, was used. A total of 352 proteins were identified and evaluated both from a qualitative and quantitative point of view. This combined approach is certainly useful to increase the final number of identifications, but no particular class of proteins was extracted and identified in spite of the different chemistries and the different precipitation protocols. However, with respect to the other two procedures, from the relative quantitative analysis, based on the number of spectral counts, the trichloroacetic acid/acetone protocol was the best procedure for sample handling and quantitative protein extraction. This study could pave the way to further high‐throughput studies on Chenopodium Quinoa.  相似文献   

6.
为考察柱色谱分离和索氏提取两种固体样品提取方法对提取物组成的影响,探索操作条件温和、溶剂使用量经济的固体样品提取方法。本研究以吡啶为溶剂,对准葛尔黑岱沟、平朔、潞安常村3种不同变质程度的煤样进行了柱色谱分离和索氏抽提。提取物用凝胶色谱、电喷雾质谱和同步荧光光谱进行分析,比较和确定不同提取方法对煤提取物中组分分子量分布和结构的影响。分析发现,柱色谱分离与索氏提取相比,抽提率略有增加,但柱色谱提取物组分中缺失了提取样品中结构稳定的超大分子结构片断;质谱结果显示柱色谱抽提物中主要存在5个组分,提取物组分相对于索氏提取物单一、富集度高;同步荧光显示柱色谱提取物中芳香化合物的基本组成为3~5个环的芳香化合物。实验结果表明:如仅分析质量数小于1000 amu的化合物,柱色谱法可替代索氏提取法。  相似文献   

7.
8.
Summary It has been shown that oil of the best quality is obtained on its selective extraction by hexane. Subsequent extraction from the meal of gossypol by 70–80% aqueous, and then dry, acetone permits meal to be obtained with a light cream color containing 0.02% of free gossypol. The omission of dry acetone leads to a darkening of the meal.It has been established that it is possible to achieve a reduction in the consumption of solvents on the direct extraction of cottonseed flake by using weak oil and gossypol miscellas.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 170–173, March–April, 1978.  相似文献   

9.
A method to determine 21 organochlorine pesticides in vegetation samples using microwave-assisted extraction (MAE) is described and compared with Soxhlet extraction. Samples were extracted with hexane–acetone (1:1, v/v) and the extracts were cleaned using solid-phase extraction with Florisil and alumine as adsorbents. Pesticides were eluted with hexane–ethyl acetate (80:20, v/v) and determined by gas chromatography and electron-capture detection. Recoveries obtained (75.5–132.7% for Soxhlet extraction and 81.5–108.4% for MAE) show that both methods are suitable for the determination of chlorinated pesticides in vegetation samples. The method using microwave energy was applied to grass samples from parks of A Coruña (N.W. Spain) and to vegetation from the contaminated industrial area of Torneiros (Pontevedra, N.W. Spain).  相似文献   

10.
Summary The oil of the seeds ofRindera oblongifolia, family Boraginaceae, growing in Central Asia, has been studied for the first time. Among the acids of the triglycerides of the oil five types of monoenoic acid differing by the length of the carbon chain but having the same length of the terminal carbon chain — 18:19, 20:111, 22:113, 24:115, and 26:117 — have been detected for the first time. This is the first time that the last of these acids has been found in a seed oil of this family.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 26–29, January–February, 1976.  相似文献   

11.
Curcuma root (Curcuma longa L.) is a very important plant in gastronomy and medicine for its unique antiseptic, anti-inflammatory, antimicrobial and antioxidant properties. Conventional methods for the extraction of curcuma oil require long extraction times and high temperatures that can degrade the active substances. Therefore, the objectives of the present study were: (i) first, to optimize the extraction yield of curcuma oil by applying a Box-Behnken experimental design using surface response methodology to the microwave-assisted extraction (MAE) technique (the independent variables studied were reaction time (10–30 min), microwave power (150–200 W) and curcuma powder/ethanol ratio (1:5–1:20; w/v); and, (ii) second, to assess the total phenolic content (TPC) and their antioxidant activity of the oil (at the optimum conditions point) and compare with the conventional Soxhlet technique. The optimum conditions for the MAE were found to be 29.99 min, 160 W and 1:20 w/v to obtain an optimum yield of 10.32%. Interestingly, the oil extracted by microwave-assisted extraction showed higher TPC and better antioxidant properties than the oil extracted with conventional Soxhlet technique. Thus, it was demonstrated that the method applied for extraction influences the final properties of the extracted Curcuma longa L. oil.  相似文献   

12.
The extraction method of pharmaceutical and personal care products (PPCPs) has become a popular issue due to the emergence of PPCPs as contaminants. In this work, polycyclic musks, a typical type of PPCPs, were selected to test various techniques including microwave-assisted extraction (MAE), simultaneous distillation-solvent extraction (SDSE), Soxhlet extraction (SE), and ultrasound probe (UP). MAE and UP proved to be more effective pretreatment techniques than SE and SDSE, with high recovery, repeatability, accuracy, efficiency, little solvent consumption, and acceptable matrix effects. Notably, the chemical methods usually did not work well for the determination of bioavailability and the environmental fate of pollutants was overestimated. In this work, wheat (Triticum aestivum L.) was used as the ecological receptor to evaluate the bioavailability of chemical pollutants. The concentrations of polycyclic musks in sediments by way of UP extraction had a significant correlation (R 2?>?0.9, P?<?0.01) with the concentrations in roots of wheat and the changes of chlorophyll, malondialdehyde and peroxidase in leaves of wheat. These changes suggest that the concentrations of polycyclic musks in sediments using UP extraction were comparable with the level of those in vivo. Through this work, it was discovered that using UP with a different solvent was suitable for determining total concentrations and the bioavailable fractions in sediments.  相似文献   

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15.
《Analytical letters》2012,45(15):2161-2175
An on-line Soxtec extraction and cleanup method is optimized for PCBs determination in mussel samples. Soxtec extraction conditions have been optimized using two factorial designs. Optimized extraction parameters were sample weight, anhydrous sodium sulfate weight, solvent volume, alumina weight, and boiling and rinsing times. The results suggest that all PCBs congeners extracted by Soxtec appeared statistically affected by solvent volume. Soxtec quantitative recoveries (8– ?115%) were achieved for all PCBs and method precision (RSD <12%) was satisfactory. The optimized method is compared with three different applied extraction methods, Soxhlet, accelerated solvent extraction, and microwave-assisted extraction. This latter presents the cleanup step on column or assisted by polypropylene membranes. The extraction effectiveness of the four different applied extraction methods for the determination of PCBs in mussel was similar.  相似文献   

16.
17.
Journal of Thermal Analysis and Calorimetry - In this study, mixed convection heat transfer of the non-Newtonian power-law nanofluid including CuO nanoparticles, inside a partially porous square...  相似文献   

18.
采用气相色谱-质谱法对超声波萃取与索氏萃取丙烯腈-丁二烯-苯乙烯(ABS)中四溴双酚A进行了比较研究。超声波萃取的最优试验条件:溶剂为二氯甲烷,温度为30℃,时间为60min;索氏萃取的最优试验条件:溶剂为甲苯,回流次数为每小时4次,时间为12h。四溴双酚A的质量浓度在1.00~100mg·L-1范围内与其峰面积呈线性关系。索氏萃取的萃取率高于超声波萃取的萃取率,索氏萃取的相对标准偏差(n=6)为2.1%,加标回收率在80.4%~85.7%之间。  相似文献   

19.
Summary 1. The fatty-acid compositions of the seed oils of catalpas cultivated in the Soviet Union have been studied.2. The oil content of the seeds is 21.2–36.7%, the refractive index 1.4905–1.5400, and the iodine number 184.8–201.7.3. The following fatty acids have been found in catalpa oil (%): palmitic — 1.3–4.3; stearic — 1.1–2.5; heneicosanoic — 0.5–5.2; oleic — 5.5–9.8; linoleic — 39.6–50.3; linolenic — 0.4–1.8; and eleostearic — 32.8–46.2.4. The most accurate results for characterizing the degree of unsaturation of the fatty acids of the catalpa seed oils are given by Woburn's method of determining iodine numbers. The iodine numbers obtained experimentally agree with those calculated and consequently the addition of halogen to the system of double bonds takes place at all the double bonds.5. The degree of unsaturation of the fatty acids of catalpa oil characterized by the iodine numbers and refractive indices increases in the sequence of species southern, northern, teas, Chinese and has a tendency to rise on passing to more northerly zones, which is one more piece of evidence confirming the correctness of S. L. Ivanov's climatic theory of the structure of fats.Kalinin Polytechnic Institute. Moscow Branch of the All-Union Scientific-Research Institute of Fats. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 331–337, May–June, 1977.  相似文献   

20.
Poly(Divinylbenzene)PolyHIPE (Poly(DVB)PolyHIPE) was successfully prepared by using two different systems of three-component surfactants (S20M and S80M) and toluene as porogenic solvent. Phase morphology, mechanical properties and surface area measurements of the obtained Poly(DVB)Poly HIPE were investigated. After polymerization of continuous phase followed by extraction process, the porous materials (open cellular structure with interconnections) were obtained. The cell size and surface area were found to be improved: this is due to the ability of porogenic solvent and mixture of the surfactants to prevent the Ostwald ripening (coalescence) of the emulsion droplet system. Moreover, the surface area and mechanical properties of the resulting materials were found to be depended on the Soxhlet extraction time. It was demonstrated that the usage of Soxhlet extraction technique for Poly(DVB)PolyHIPE improved surface area of the obtained materials by 107% as compared with the unextracted PolyHIPE. However, when the extraction time was longer than 12 hours, the properties of the obtained materials became poor. It was concluded that the suitable Soxhlet extraction time for Poly(DVB)PolyHIPE was 6–12 hours and at this condition, high surface area with the highest mechanical properties of the porous material were obtained.  相似文献   

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