密闭微波辅助萃取当归粉中的阿魏酸

利用密闭微波样品制备系统(具有压力控制部件),对当归中的有效成分阿魏酸的萃取进行研究,比较了密闭微波萃取同超声波萃取和索氏萃取阿魏酸提取率的差异.结果表明:微波萃取与其他两种萃取方法相比,具有速度快和萃取率高的特点.并得到了阿魏酸提取的最佳条件:微波功率为400 W,萃取剂为90%的乙醇(体积分数),固-液比为1∶15,微波辐射为240 s,当归粒径为75μm.     

微波辅助萃取新鲜芦荟叶中芦荟甙的研究

应用密闭微波萃取装置对芦荟中的有效成分芦荟甙进行了微波萃取研究,并利用透射电子显微镜对微波萃取机理进行了初步探讨.讨论了不同萃取剂、溶剂浓度、萃取时间和微波功率等对提取率的影响.在萃取剂为乙醇-水体系,溶剂(乙醇)体积分数为70%、萃取时间为4min及微波功率为340W的条件下,萃取效果最佳.与索氏提取及超声波萃取法相比,本法具有萃取速度快、提取率高及溶剂用量少等特点.     

密闭微波辅助萃取天麻中天麻素的研究

应用密闭微波萃取装置,对中药天麻中有效成分天麻素的萃取进行了研究。分别讨论了药材颗粒粒径、提取溶剂浓度、微波提取时间和提取剂的用量对微波萃取天麻素的影响。结果表明:当药材粒径<50μm,乙醇体积分数为50%,微波辐射时间为2min,提取剂质量为药材质量的30倍时,天麻素提取率最高。此外,将微波萃取与索氏萃取和超声波萃取进行了比较。     

L-半胱氨酸衍生物配体交换手性色谱固定相

应用密闭微波萃取装置对芦荟中的有效成分芦荟甙进行了微波萃取研究,并利用透射电子显微镜对微波萃取机理进行了初步探讨,讨论了不同萃取剂、溶剂浓度、萃取时间和微波功率等对提取率的影响,在萃取剂为乙醇-水体系,溶剂（乙醇）体积分数为70％、萃取时间为4min及微波功率为340W的条件下,萃取效果最佳,与索氏提取及超声波萃取法相比,本法具有萃取速度快、提取率高及溶剂用量少等特点。     

一种新型微波辅助萃取法用于中药刺五加中总黄酮萃取的研究

微波萃取法是目前世界上公认的绿色样品预处理技术之一 .它在环境、生化、食品、工业以及天然产物和中药等领域均有广泛的应用 [1～ 4 ] .目前 ,最常用的微波萃取系统有两种 [5] ,一种是使用多模式微波炉 ,在密闭容器中加热样品及有机溶剂 ,将目的组分从样品基体中萃取出来 .由于在密闭容器中 ,被萃取样品和溶剂处于高压下 ,温度很高 ,使待萃取物的溶解度增大 ,可获得更高的萃取率 .同时 ,用于这种微波萃取的系统一般可同时容纳 9～ 1 2个萃取罐 ,使试样的批量处理能力大大提高 .该法最主要的缺点是萃取后的液体一般需经离心分离或微孔玻璃…     

微柱高效液相色谱法测定丹参中的几种有效成分

研究了用微柱高效液相色谱法测定丹参中的4种有效成分(丹参素,原儿茶酸,原儿茶醛,丹酚酸B)的方法。丹参样品中的几种有效成分用体积分数40%的甲醇超声振荡提取,然后以WatersXterraTMRP18(1.0×50mm,2.5μm)微柱为固定相,甲醇和体积分数1%的HAc溶液梯度洗脱为流动相分离,在该色谱条件下,丹参中的4种有效成分在4.0min内可达到基线分离;用紫外二极管矩阵检测器检测。方法标准回收率为97%~102%,相对标准偏差为1.6%~2.3%。用此方法可测定几种丹参样品中的有效成分。     

微波辅助萃取与超声波萃取丹参中丹酚酸B的比较研究

本文对微波辅助萃取和超声波萃取丹参中丹酚酸B进行了比较研究,并用高效液相色谱法(HPLC)测定了丹参中丹酚酸B.考察了微波辅助萃取和超声波萃取参数的影响,在各自最佳萃取条件下进行了丹参中的丹酚酸B提取率的比对,结果表明:微波辅助萃取6 min的提取率高于超声波萃取30 min的提取率.微波辅助萃取法与超声波萃取法相比具有省时、高效和溶剂用量少的特点.利用指纹图谱比较了两种萃取方式提取的化学成分的差异,结果显示两种萃取方法提取的主要成分组成基本相同,其共有成分比例相近.     

超声-微波协同萃取分离、气相色谱-质谱联用测定土壤中多环芳烃

建立了常温常压条件下超声-微波协同萃取分离、气相色谱-质谱法（GC-MS）测定土壤样品中微量多环芳烃的方法,结果表明：在土壤含水量和无机盐质量分数分别为10％和6％时,以正已烷-二氯甲烷（1＋1）混合溶液40mL作萃取溶剂,采用100W微波辐射功率（超声振动功率固定为50W）萃取9min,模拟土壤样品中多环芳烃平均回收率可达86．9％,其相对标准偏差为3．6％;通过与索氏抽提、高压密闭微波和开放式微波、直接超声波和间接超声波等萃取方法相比,证明此方法具有样品容量大、萃取时间短、萃取效率高、重现性好等优点。     

藜蒿中黄酮类化合物的微波辅助萃取研究

应用密闭微波萃取装置，分别对藜蒿茎和藜蒿叶中黄酮类化合物进行微波萃取研究。采用正交试验方法得到微波提取藜蒿中黄酮类化合物的最佳条件。微波提取藜蒿茎的最佳条件为乙醇体积分数70％，微波功率800W，提取温度80℃和料液比1：20；微波提取藜蒿叶的最佳条件为乙醇体积分数70％，微波功率600W，照射时间12min，提取温度70℃和料液比1：20；在最佳条件下，藜蒿茎和叶中总黄酮提取率分别为6．43％和7．01％。并将微波萃取与乙醇回流提取进行了比较。     

超声-微波协同萃取装置用于土壤中多环芳烃的分析

本研究将开放式微波和直接超声波振荡两种不同的能量方式相结合,研制出超声-微波协同萃取装置。通过萃取土壤中微量多环芳烃(PAHs),对方法和仪器的可行性进行了初步评价。结果表明,在60 mL二氯甲烷-正已烷(1∶1,V/V)的混合萃取剂,100 W微波辐射功率(超声振动功率固定为50 W),萃取9~10m in,土壤中多环芳烃回收率达86.6%,相对标准偏差约4.0%。与索氏抽提、高压密闭和开放式微波等萃取方法相比,本方法具有样品容量大,萃取时间短,萃取效率受样品中含水量和溶剂极性影响小等优点。     

Optimization of Microwave-Assisted Extraction for the Determination of Organic Flame Retardants in Acrylonitrile Butadiene Styrene

The efficiency of microwave-assisted extraction was evaluated for the determination of flame retardants in acrylonitrile butadiene styrene by optimization of the temperature, time, and solvent. A quality control sample containing 500 milligrams per kilogram Dechlorane Plus, 1000 milligrams per kilogram tetrabromobisphenol A, and 1000 milligrams per kilogram triphenyl phosphate was employed. The flame retardant concentrations obtained by microwave-assisted extraction at 120 degrees Celsius for ten minutes in tetrahydrofuran were in agreement with those for the quality control sample. The efficiency of microwave-assisted extraction was comparable to ultrasonic and Soxhlet extraction used as reference techniques. In addition, the repeatabilities of the analyses, represented as relative standard deviations, were comparable: 0.8–3.4 percent for microwave-assisted extraction, 0.3–3.3 percent for ultrasonic extraction, and 0.2–8.5 percent for Soxhlet extraction. These results suggest that microwave-assisted extraction is suitable for the determination of Dechlorane Plus, tetrabromobisphenol A, and triphenyl phosphate in acrylonitrile butadiene styrene.     

微波辅助-旋转回流提取叶下珠中的没食子酸

A new kind of microwave-assisted circumrotation reflux extraction device was constructed and used to study the extraction technology of gallic acid from phyllanthus urmaria L.The extraction principle of the device was same as that of microwave-assisted solvent extraction but using circumrotation techniques as auxiliary stirrer to accelerate the process.Capillary electrophoresis was used to determinate gallic acid in phyllanthus urmaria L extracts in order to evaluate the extraction efficiency of the method.It was found that the most important factors influencing extraction gallic acid were solvent kind and microwave power.The optimum extraction conditions were as follows:water using as irradiate time 4 minute.Under the optimum extraction conditions,five experiments were carried out and the average extraction rate of gallic acid in phyllanthus urmaria L was 4.32 mg/g,relative standard deviations (R.S.D.) was 2.2%.Compared with other extraction methods e.g.reflux extraction and microwave-assisted extraction,better extraction efficiency was observed for the microwave-assisted circumrotation reflux extraction.     

Determination of adipate plasticizers in poly(vinyl chloride) by microwave-assisted extraction

A new method based on the application of microwave radiation to the extraction of adipate plasticizers from poly(vinyl chloride) PVC plastics is described. The experimental conditions for microwave-assisted extraction (i.e. extracting solvent, temperature, time and microwave power) were evaluated in terms of recovery. The optimisation was carried out with pastes of PVC plastified with di-2-ethylhexyl adipate, and extracts were measured by gas chromatography with flame ionization detection. Six different adipate plasticizers were studied, and microwave-assisted extraction was compared with supercritical fluid extraction for the extraction of adipates and phthalates from PVC matrices. It has been observed that the microwave-assisted extraction parameters evaluated are tightly interconnected. It has been shown that the efficiency of microwave-assisted extraction depends on the kind of solvent, the temperature achieved and the heating time. Moreover, the final temperature reached depends on the microwave power, the number of vessels and the irradiation time. On the other hand, microwave-assisted extraction provides higher recovery values than supercritical fluid extraction for both phthalate and adipate plasticizers.     

Microwave-assisted extraction performed in low temperature and in vacuo for the extraction of labile compounds in food samples

In this study, low temperature vacuum microwave-assisted extraction, which simultaneous performed microwave-assisted extraction (MAE) in low temperature and in vacuo environment, was proposed. The influencing parameters including solid/liquid ratio, extraction temperature, extraction time, degree of vacuum and microwave power were discussed. The predominance of low temperature vacuum microwave-assisted extraction was investigated by comparing the extraction yields of vitamin C, β-carotene, aloin A and astaxanthin in different foods with that in MAE and solvent extraction, and 5.2–243% increments were obtained. On the other hand, the chemical kinetics of vitamin C and aloin A, which composed two different steps including the extraction step of analyte transferred from matrix into solvent and the decomposition step of analyte degraded in the extraction solvent, were proposed. All of the decomposition rates (K₂) for the selected analyte in low temperature, in vacuo and in nitrogen atmosphere decreased significantly comparing with that in conventional MAE, which are in agreement with that obtained from experiments. Consequently, the present method was successfully applied to extract labile compound from different food samples. These results showed that low temperature and/or in vacuo environment in microwave-assisted extraction system was especially important to prevent the degradation of labile components and have good potential on the extraction of labile compound in foods, pharmaceutical and natural products.     

微波辅助-旋转回流提取仪的组装及其在叶下珠有机酸提取中的应用

组装了一种新型的微波辅助旋转回流装置,该装置的基本原理与微波辅助溶剂萃取的原理相同,但采用了旋转的技术以加速提取.应用该装置以正交实验筛选优化叶下珠中有机酸的提取工艺,并利用毛细管电泳技术分离测定了提取液中有机酸的含量以评价提取效果.最佳提取工艺:乙醚为溶剂,微波功率800 W,提取时间4 min,溶剂用量300 mL.在该提取条件下,平行5次提取叶下珠中丁二酸、原儿茶酸、没食子酸、咖啡酸、阿魏酸的平均含量分别为42.2、103.5、436.2、123.8、67.4 μg/g,相对标准偏差为0.87% ～3.7%,加标回收率为94% ～104%.将该法与常规的微波辅助提取法及回流提取法进行比较,结果表明,微波辅助旋转回流提取法提取效率明显优于其它2种方法.     

微波辅助萃取鬼箭羽叶中芦丁和槲皮素

建立了鬼箭羽中主要有效成分芦丁和槲皮素的MAE-HPLC定量分析方法, 该方法具有测定准确、操作简便和分析速度快等优点. 此外, 利用扫描电镜观察了鬼箭羽叶经微波辅助萃取后植物结构的变化, 初步证明了微波辅助萃取鬼箭羽叶的萃取机理符合细胞破壁学说.     

Determination of triazines in soil by microwave-assisted extraction followed by solid-phase microextraction and gas chromatography-mass spectrometry

A method for determining triazine herbicides in soil samples that combines microwave-assisted extraction with solid-phase microextraction is described. Water containing 1% methanol was employed as extractant. The parameters of solid-phase microextraction and microwave-assisted extraction were investigated. In solid-phase microextraction, particular attention was paid to the negative effect of salt on fiber stability. Our experiments showed that this effect could be effectively reduced by simply washing the fiber with deionized water. The selected triazines could be efficiently extracted by the aqueous extractant at 105 degrees C for 3 min, with 80% output of maximum power (1,200 W). The extraction procedure provided good precision (<7%) and recoveries (76.1-87.2%). The limits of detection were in the range 2-4 microg/kg. Compared with conventional liquid extraction, microwave-assisted extraction-solid-phase microextraction was more efficient, accurate and faster, and used a very small amount of organic solvent (only 250 microL methanol). The extraction of aged spiked soil samples indicated that, although the recoveries were lower than those of freshly spiked samples, they were nevertheless satisfactory for the quantitative analysis of real-world samples.     

Microwave-assisted extractions of active ingredients from plants

Microwave-assisted extraction (MAE) is widely employed in the analysis and the extraction of active compounds from plants. This review summarizes the research done during the last decade on the MAE of active ingredients from plants. Advances and modifications to improve the performance of MAE are presented and discussed in detail. Modified MAE such as vacuum microwave-assisted extraction (VMAE), nitrogen-protected microwave-assisted extraction (NPMAE), ultrasonic microwave-assisted extraction (UMAE), dynamic microwave-assisted extraction (DMAE) and other advancements in MAE are also detailed in this article. In addition, the microwave extraction procedures and the important parameters influencing its performance are also included, together with the advantages and the drawbacks of each MAE techniques.     

Application of non-ionic surfactant in the microwave-assisted extraction of alkaloids from Rhizoma Coptidis

The feasibility of employing non-ionic surfactant oligoethylene glycol monoalkyl ether (Genapol X-080) as an alternative and effective solvent for the microwave-assisted extraction of alkaloids from Rhizoma Coptidis was demonstrated. When compared with commonly used solvents, 5% Genapol X-080 enhanced the extraction efficiency. Under optimal conditions, i.e. 5% acidified Genapol X-080 (v/v), microwave-assisted extraction for 10 min at 100 °C, the extraction recovery of alkaloids reached 92.8% in a one-step extraction. The efficiency of cloud-point preconcentration of three alkaloids was in the range 93.6-94.7% with relative standard deviation lower than 3.3% by the proposed procedure. Furthermore, the combination of microwave-assisted extraction and cloud-point extraction was shown to be a green, rapid and effective approach for alkaloids preconcentration of Rhizoma Coptidis samples.