首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   32篇
  免费   2篇
  国内免费   2篇
化学   26篇
综合类   1篇
物理学   9篇
  2020年   1篇
  2018年   1篇
  2016年   2篇
  2014年   1篇
  2013年   2篇
  2012年   2篇
  2011年   1篇
  2010年   3篇
  2009年   4篇
  2008年   4篇
  2007年   2篇
  2006年   1篇
  2005年   4篇
  2004年   2篇
  2002年   1篇
  2000年   1篇
  1990年   1篇
  1981年   1篇
  1976年   1篇
  1973年   1篇
排序方式: 共有36条查询结果,搜索用时 893 毫秒
1.
Isoquinoline alkaloids are the primary active ingredients of Corydalis, but an analytical method for quality assessment of the active ingredients in Corydalis impatiens (Pall). Fisch has not been reported. A new, simple, and multiple‐component quantification method was developed for the simultaneous quantification of 11 isoquinoline alkaloids including capnoidine, chelianthifoline, bicuculline, protopine, isoapocavidine, apocavidine, cavidine, tetrahydroepiberberine, ochotensimine, tetrahydrocoptisine, and tetrahydrocorysamine in C. impatiens. Separation of the isoquinoline alkaloids was performed on a RP C18 column (150 × 4.6 mm, 5 μm) with potassium dihydrogen phosphate buffer (pH 2.5, adjusted by phosphoric acid)/acetonitrile (53:47, v/v) containing 0.3% sodium dodecyl sulfonate. The flow rate and detection wavelength were set at 1 mL/min and 295 nm, respectively. Full validation of the assay was carried out including linearity, precision, accuracy, stability, LOD, and limit of quantitation. All calibration curves showed a good linear relationship (r > 0.999) in test range. The results demonstrated that the developed method was reliable, rapid, and specific. Six batches of C. impatiens samples from different sources were determined using the established method. The contents of alkaloids ranged from 11.68 to 351.83 μg/g. This method can be applied for quality evaluation and control of C. impatiens. Eleven isoquinoline alkaloids were first reported on simultaneous determination with HPLC.  相似文献   
2.
The herbal combination is the basic unit of a herbal formula that affects the chemical characteristics of individual herbs. In the present study, a method of simultaneous determination of the 11 marker compounds in Jakyakgamcho‐tang was developed using high‐performance liquid chromatography with photodiode array detection. The validated analytical method was successfully applied to approach the chemical interaction between Paeonia lactiflora and Glycyrrhiza uralensis in co‐decoction. In P. lactiflora, the contents of gallic acid, oxypaeoniflorin, (+)‐catechin, paeoniflorin, and benzoylpaeoniflorin were decreased, while those of albiflorin and benzoic acid were increased; in G. uralensis, the contents of liquiritin, isoliquiritin, ononin, and glycyrrhizin were decreased, when decocting two herbs together. Moreover, as the ratio between P. lactiflora and G. uralensis was increased, the contents of chemical contents from each herb were proportionally increased. However, each content of marker compound per the gram of herbal medicine was decreased as the ratio of combinative herbs increased. The results showed that P. lactiflora and G. uralensis affect the extraction efficiency of chemical compounds in a Jakyakgamcho‐tang decoction. Overall, the method established in this study was simple, rapid, and accurate, and would be useful for the determination of marker compounds and for the investigation of the chemical interaction between herbal medicines.  相似文献   
3.
子午岭野菊花挥发油的化学成分及抑菌活性   总被引:7,自引:0,他引:7  
利用GC—MS联用法对野菊花挥发油的化学成分进行了分析研究.在最佳分析条件下.共分离出39个化学成分.鉴定出了其中的38个.主要成分为:萜类、酚类、有机酸及其酯等化合物.对挥发油的抗菌活性进行了初步研究.为今后对野菊花药理活性的研究提供了重要的理论依据.  相似文献   
4.
负压空化提取甘草酸工艺   总被引:1,自引:0,他引:1  
负压空化提取甘草酸工艺;负压空化;甘草;甘草酸;提取  相似文献   
5.
以正十四烷为内标,采用气相色谱-质谱(GC/MS)联用技术对中药甘草(GUF)、甘遂(EKL)单味药材,以及其组成的药对(GUF-EKL)的挥发成分进行测定,基于一种新的化学计量学方法——转换移动窗口因子分析法(AMWFA)和直观推导式演进特征投影法(HELP)对产生的二维色谱/质谱数据同时进行分辨和解析,获取各个组分的纯色谱曲线和质谱,根据分辨得到的纯质谱在质谱库中进行相似检索以实现对组分的定性。利用AMWFA对组合前后的成分进行归属分析,然后采用面积归一法进行定量。分别在甘草、甘遂及其药对中鉴定出52、51和63个成分,占各自挥发油成分的84%、90%和75%。  相似文献   
6.
IntroductionWater is an ubiquitous and indispensable moleculefor plant growth and development[1]. According to thecomposite water flux model[2], water is transported intoplant tissues by three pathways: apoplastic, symplas-tic, and transcellular. The latt…  相似文献   
7.
应用高效液相色谱质谱联用方法(HPLC-ESI-MSn)研究了甘草提取物中的七种化合物,四种三萜类化合物和三种黄酮类化合物。通过多极串联质谱(ESI-MSn)和多极串联傅里叶变换回旋共振质谱(FT-ICR-MSn)法研究了它们的碎裂规律。通过比较保留时间和质谱数据对上述七种化合物进行了归属,并阐述了其可能的质谱裂解途径。以上结果显示ESI-MSn和FT-ICR-MSn是非常有效的分析三萜类化合物和黄酮类化合物结构的工具。  相似文献   
8.
This work aimed to investigate the α-glucosidase inhibitor from the roots of Glycyrrhiza uralensis Fisch. Seven flavonoids were isolated, and the total content of compounds 1–7 were more than 50% in Glycyrrhiza total flavones (GTF), and the content of compound 1 and 2 was abundant in GTF. The results of the α-glucosidase inhibitory activities indicated that compounds 1–6 and GTF respectively with the IC50 values of 31.303, 30.263, 23.363, 19.528, 10.854, 26.454 and 21.641 μg/mL exhibited the more potent activity than acarbose with the IC50 values of 38.995 μg/mL. These result suggested that Glycyrrhiza flavonoids may become a valid alternative of potential basis for new hypoglycaemic and antidiabetic agents.  相似文献   
9.
Magnetic separation technology was applied in the separation of flavonoids from the licorice root in this work. Licorice flavonoids (LF) displayed a remarkable array of biological and pharmacological activities. The magnetic adsorbents with functional —NH2 groups were synthesized by immobilization of amino-silane on the surface of the magnetic silica supports, which were prepared by co-precipitation method. The adsorption and desorption characteristics of the magnetic adsorbents for the separation of LF have been evaluated. The purity of an enriched extract with this method was 16.7% while the crude extract only had about 6.8% purity. Therefore, it can be concluded that these kinds of magnetic adsorbents have selectivity to the flavonoids to some extent. The affinity selectivity of the adsorbents is based on the formation of hydrogen bonding between the —NH2 on the magnetic adsorbents and —OH, —CO on the flavonoids. Supported by the National High Technology Research and Development Program of China (Grant No. 2002AA302211) and the National Science Fund for Creative Research Groups of China (Grant No. 20221603)  相似文献   
10.
采用水提醇沉法制备黄芪多糖提取物,苯酚-硫酸分光光度法测定多糖的含量,在0.00-0.14mg/mL线性范围内具有良好的线性关系,回收率在94.81%-103.50%.测定黄芪多糖含量为4.3%.采用校准曲线法,用空气-乙炔火焰原子吸收光谱法测定样品中Fe、Zn、Cu和Mn的含量,膜荚黄芪中微量元素含量较高.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号