中药大黄中蒽醌的微波辅助流动萃取研究

利用微波辅助流动萃取法提取大黄中的蒽醌类化合物，考察了微波提取条件(包括溶剂浓度、微波辐射功率、溶剂提升量)对大黄中葸醌提取率的影响，采用分光光度法测定提取液中蒽醌的含量．结果表明溶剂为60%乙醇，提升量为4mL／min，微波功率为80％时，提取效率最佳．微波辅助流动萃取法与超声波法和索氏提取法相比，具有提取效率高，时间短且节能的良好特点．     

火焰原子吸收光谱法测定尘铅前处理方法的研究

采用火焰原子吸收光谱法测定尘铅样品,在0-1．00mg／L范围内样品中铅含量与吸光度呈良好线性关系,检出限为2．88μg／m^2（按定容体积50mL、采样体积400L计）。采取酸煮法、索氏提取法、微波消解法、超声波提取法等4种前处理方法,在0．100,0．500,1．00mg3个质量水平对空白滤筒进行加标回收试验,4种前处理方法的回收率和测定结果的相对标准偏差分别为91．8％-97．4％,2．2％～3．2％;83．0％-86．8％,7．4％-10．3％;93．6％-97．2％,2．5％～3．7％;89．3％-90．9％,3．2％～4．5％,提取效果以酸煮法和微波消解法最佳,超声波提取法次之,索氏提取法最差。     

黄芪中主要活性成分的分离提取研究进展

皂苷、黄芪多糖和黄酮是中药磺芪的主要有效成分,其提取方法各有不同,如超声提取法、回流法、索氏提取法、高速离心法、超滤法等均有应用,既提高收率,又降低成本.     

Optimization of extraction technology of total flavonoids from toots of chenopodium glaucum (L.)using response surface methology

采用响应面法优化微波提取藜根黄酮的条件.在单因素试验的基础上,选取乙醇体积分数、微波提取时间、液料比为影响因子,应用Box-Behnken中心组合进行3因素3水平的试验设计,以藜根黄酮得率为响应值,进行响应面分析.结果表明,微波提取藜根黄酮的最佳提取条件为:乙醇体积分数70％、液料比16:1、微波功率500W、微波时间6min.在此优化工艺下藜根黄酮的得率为0.80％,即8.0mg/g.     

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.     

微波辅助提取-可见分光光度法测定穿心莲中的总黄酮

比较了微波辅助提取、超声提取、索氏提取3种方式对穿心莲中总黄酮的提取效率.确定以微波辅助提取法最佳.实验结果表明:用60%乙醇在固液比为1:15的条件下提取6 min提取效率最高.用NaNO2-硝酸铝-NaOH-黄酮体系分光光度法测定总黄酮含量,平均回收率为103.00%,RSD=1.37%(n=5),证实了可以用微波辅助提取法提取,紫外可见分光光度法检测穿心莲中总黄酮的可行性.     

响应面法优化微波提取翻白草总黄酮

利用响应面法研究了翻白草总黄酮的微波辅助提取工艺.在单因素试验的基础上,以乙醇体积分数、液固比、提取温度、微波时间为自变量,总黄酮的得率为响应值,研究各因素及其交互作用对黄酮得率的影响.结果表明其最佳提取条件是:乙醇体积分数55%、液固比32 m L/g、温度82℃、微波时间10 min.此条件下,翻白草中黄酮的提取率为6.96 mg/g,与理论预测值基本吻合.     

真空回流提取-高效液相色谱法测定灯盏花中的槲皮素

云南具有丰富的植物和药物资源,其主要成分的有效提取成为高效利用的关键.本文作者采用真空回流法提取灯盏花中的槲皮素黄酮化合物,优化了提取条件,结合高效液相色谱法对提取产物进行了测定,并与常压回流提取法进行了对照;结合提取后样品的扫描电镜分析,探讨了不同提取方法对提取产物表观结构的影响.结果表明,真空联用提取法优于常压提取法,利用真空负压下的提取可避免黄酮化合物的氧化,提高提取效率.     

微波辐射-溶剂回流法提取/HPLC法测定倒提壶中天芥菜碱与毛果天芥菜碱的含量

采用单因素试验,对微波辐射-溶剂回流提取法的实验条件进行优化,得到最佳提取条件:药材颗粒度100目,微波功率60%档(总功率为700 W),微波辐射时间90 s,固液比1∶25,提取温度90℃,提取时间45 min。以天芥菜碱和毛果天芥菜碱为提取目标物,通过HPLC法测定其含量,其分析条件为:以乙腈-0.1%乙酸溶液(p H 5.6,体积比5∶95)为流动相,在220 nm处检测。毛果天芥菜碱和天芥菜碱的浓度在50~900 mg/L范围内均呈良好线性关系,检出限分别为1.50 mg/L和1.52 mg/L,加标回收率分别为95.0%~98.5%和96.5%~101%,RSD分别为1.8%和2.4%,方法简单、灵敏度高。     

人参中总皂甙的超声波快速提取方法研究

建立了人参中总皂甙超声波半微量快速提取方法，与索氏提取法相比，此法提取时间由索氏法的1－2个工作日缩短到30min，节省大量试剂，综合提取效率提高数十倍，与索氏提取法对照分析表明，此法可完全满足人参中总皂甙的快速测定要求。     

Dynamic Microwave-assisted Extraction of Flavonoids from Radix Scutellariae

IntroductionRadix Scutellariaeis the root ofScutellaria bai-calensis Georgi(Labiatae), which is widely cultivatedand used as traditional Chinese medicine. It has beendemonstrated to be anti-inflammatory, anti-metamor-phic, antiviral, anti-hot, and live pr…     

微波辅助流动萃取槐花中的黄酮类成分

槐花为豆科落叶乔木槐树(Sophora japonica L.)的花蕾,槐花能降低血管的通透性,所含芸香甙(芦丁)对心脏传导系统有抑制作用,能增强收缩力及输出量,降低血压;所含槲皮素可以扩张冠状动脉,降低心肌耗氧量,并能降低血脂。     

密闭微波辅助提取-HPLC法测定还亮草中硬飞燕草碱和巴比翠雀碱的含量

采用密闭微波辅助法(PMAE)提取还亮草中的硬飞燕草碱和巴比翠雀碱。采用单因素试验结合正交试验方法对微波实验条件进行优化。得到硬飞燕草碱和巴比翠雀碱的最佳提取方案:药物颗粒度100目,固液比1∶60,微波温度80℃,微波功率560 W,微波时间10 min。以甲醇-0.2%三乙胺(45∶55)为流动相,建立了高效液相色谱(HPLC)测定硬飞燕草碱和巴比翠雀碱含量的方法。硬飞燕草碱和巴比翠雀碱分别在0.50~50.0,0.30~30.0 mg/L范围内呈良好的线性关系,回收率为98.3%~104.5%,相对标准偏差(RSD)分别为2.0%和2.2%。与传统溶剂回流法(SRE)进行比较,该方法简单、提取率更高。     

微波萃取技术

介绍了在气相／液相色谱测定前的一种新的样品制备技术——微波萃取技术及其所使用的试剂、设备和条件。通过一些数据以及与Ｓｏｘｈｌｅｔ法、超声萃取法比较说明,微波萃取是一种快速、试剂用量少、回收率高、灵敏以及易于自动控制的方法。     

Microwave Assisted-extraction of Flavonols from Acanthopanax Senticosus Harms and High-performance Liquid Chromatography Analysis

Flavonols were extracted from Acanthopanax Senticosus Harms by Soxhlet extraction(SE),atmospheric pressure microwave-assisted extraction(AMAE) and pressurized microwave-assisted extraction(PMAE).The influences of experimental conditions,such as concentration of ethanol in the eluent,microwave irradiation time,etc.on the extraction yield were studied.Four flavonols(hyperin,rutin,quercitrin and quercetin) in the extracts were determined quantitatively by HPLC method.The experimental results demonstrate the ad...     

Extraction of nutraceuticals from milk thistle

Milk thistle contains compounds that display hepatoxic protection properties. We examined the batch extraction of silymarin compounds from milk thistle seed meal in 50, 70, 85, and 100°C water as a function of time. After 210 min of extraction at 100°C, the yield of taxifolin was 1.2 mg/g of seed, a 6.2-fold increase over the results obtained in a Soxhlet extraction with ethanol on pretreated (defatted) seeds. Similarly, the yield of silychristin was 5.0 mg/g of seed, a 3.8-fold increase. The yields of silybinin A and silybinin B were 1.8 and 3.3 mg/g of seed, respectively, or roughly 30% of the Soxhlet yield. The ratios of the extracted compounds, and particularly the ratios at long extraction times, showed that the more polar compounds (taxifolin and silychristin) were preferentially extracted at 85°C, while the less polar silybinin was favored at 100°C.     

Isolation of flavonoids from aspen knotwood by pressurized hot water extraction and comparison with other extraction techniques

Pressurized hot water extraction (PHWE) conditions (time, temperature, pressure) were optimized for the extraction of naringenin and other major flavonoids (dihydrokaempferol, naringin) from knotwood of aspen. Extracts were analysed by GC-FID, GC-MS, HPLC-UV and HPLC-MS. The results were compared with those obtained by Soxhlet, ultrasonic extraction and reflux in methanol. Flavonoids were most efficiently extracted with PHWE at 150 °C and 220 bar with 35 min extraction time. Soxhlet with methanol gave slightly higher recoveries, but an extraction time of 48 h was required. Naringenin concentration was highest in knotwood (1.15% dry weight) and much lower in the sapwood. PHWE proved to be cheap, fast and effective for the isolation of biofunctional flavonoids from aspen knotwood, producing higher recoveries than 24 h Soxhlet extraction, sonication or 24 h reflux.     

Comparison of extraction techniques for the isolation of explosives and their degradation products from soil

A comparison of four extraction techniques used for the isolation of 14 explosive compounds (Method 8330-Explosives) from spiked soil samples is described. Soxhlet warm extraction (SWE), pressurized solvent extraction (PSE), microwave assisted extraction (MAE) and supercritical fluid extraction (SFE) were included. The effects of basic extraction conditions – i.e. type of extraction solvent, temperature, pressure, and extraction time – were investigated. The best extraction recovery of the monitored compounds from spiked soil was obtained using pressurized solvent extraction. Recoveries of explosives using the PSE technique were in the range from 65 to 112%. Extraction recoveries by Soxhlet warm extraction and supercritical fluid extraction reached 65–99% and 52–75%, respectively. The lowest extraction recoveries (28–65%) were obtained using microwave assisted extraction. A very low extraction recovery for tetryl was observed in all cases but the best results were achieved by pressurized solvent extraction (58%).     

Evaluation of pressurized liquid extraction and pressurized hot water extraction for tanshinone I and IIA in Salvia miltiorrhiza using LC and LC-ESI-MS

Pressurized liquid extraction (PLE) and pressurized hot water extraction (PHWE) using a laboratory-made system are applied for the extraction of thermally labile components such as tanshinone I and IIA in Salvia miltiorrhiza. PLE and PHWE are carried out dynamically at a flow of 1 mL/min, temperature between 95-140 degrees C, applied pressure of 10-20 bars, and extraction times of 20 and 40 min, respectively. Effects of ethanol added into the water used in PHWE are explored. PLE is found to give comparable or higher extraction efficiencies compared with PHWE with reference to Soxhlet extraction for tanshinone I and IIA in Salvia miltiorrhiza. The tanshinone I and IIA present in the various medicinal plant extracts are determined by liquid chromatography and liquid chromatography-mass spectrometry.     

Influence of extraction methods on stability of flavonoids

The LC-MS/MS was applied for the determination of flavonoids' stability under four types of solvent extraction methods (reflux heating, sonication, maceration and microwave) from maize samples. The 11 flavonoids belong to different groups: flavonols (kaempferol, myricetin, rhamnetin, quercetin, rutin), flavanones (naringenin, naringin, hesperedin), flavones (apigenin, luteolin), isoflavones (genistein) were studied. The effect of the degradation of flavonoids depended on extraction mode and chemical structure. The smallest decomposition was observed by heated reflux extraction procedure within 30 min in water bath and by microwave assisted extraction under 160 W during 1 min. The decomposition for flavonoids depends on number of substituents in flavonoid molecule. The most unstable compound (recovery below 50%) in tested condition was myricetin. The higher number of hydroxyl groups promote degradation of flavonoids, whereas sugar moiety and methoxyl groups protect flavonoids of degradation during microwave and ultrasonic assisted extraction.