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1.
采用气相色谱法跟踪测定了α-蒎烯氧化反应中主产物蒎酮酸的含量;实验结果表明,在SE-30/Chro-mosorb W/AW(0.25-0.175mm)的色谱柱上,蒎酮酸与副产物之间具有较好的分离效果,并且在峰形对称性和出峰时间上,SE-30柱也具有优势;该法操作简便、快速、准确性高、重复性好;对同一试样的5次平行独立测定的相对标准偏差(RSD)为1.8%;该法的标准加入回收率达88%-96%。  相似文献   

2.
在pH 4.1的BR缓冲溶液中,乙基紫(EV)与七叶皂苷钠(SA)作用,形成离子缔合物,溶液颜色发生明显褪色.其最大褪色波长位于594 nm处,七叶皂苷钠的质量浓度与褪色强度呈正比,七叶皂苷钠的质量浓度在0.15~35.0μg/mL范围内遵守比尔定律,相关系数为R=0.9995,摩尔吸光系数为2.5×104L·mol-1·cm-1,检出限为45.8 ng/mL.该方法已用于片剂和尿样中七叶皂苷钠的测定.  相似文献   

3.
反相高效液相色谱法测定中药中薯蓣皂苷元   总被引:18,自引:0,他引:18  
用反相高效液相色谱法分离并测定了穿山龙、粉草解、胡芦巴、七叶一枝花、山药等5种中草药中的薯蓣皂苷元,建立了中药中薯蓣苷元的液相色谱分离测定方法,色谱条件:ODS柱,甲醇-水(95+5)为流动相,紫外检测波长209nm.  相似文献   

4.
采用单阀双阳离子交换树脂微柱并联,设计了双路采样逆向洗脱在线分离富集系统,该系统与原子吸收导数测量技术相结合,实现了在线分离富集.导数火焰原子吸收光谱法同时测定水中Cr(Ⅲ)和Cr(Ⅵ),导数仪用2mV/min档位,富集lmin时,分析速度为60样/h,测定Cr(Ⅲ)和Cr(Ⅵ)的特征浓度分别为0.448μg/L和0.793μg/L(相当于1%导数吸收度),线性范围分别为0-90和0-180μg/L;对浓度分别为10、20μg/LCr(Ⅲ)和Cr(Ⅵ)测定的相对标准偏差分别为2.85%和2.85%;检出限分别为0.855和1.7lμg/L.该法对实际水样加标回收率在94.7%.104%之间。  相似文献   

5.
在pH值为4.5~5.5的BR缓冲溶液中,七叶皂苷钠(SA)阴离子与夜蓝(NB)阳离子反应,形成1:1的离子缔合物并引起共振瑞利光散射(RRS)急剧增强和产生新的RRS.最大散射波长位于416nm处,并且七叶皂苷钠质量浓度在0.025~20×10-6g/mL范周内与散射强度(ΔI)呈线性关系,用于七叶皂苷钠分析具有较高的灵敏度,检出限为7.5×10-9g/mL.研究了适宜的分析条件和影响因素,共存物质的影响研究表明,方法的选择性较好,可满足针剂、片剂及尿液中七叶皂苷钠的测定.  相似文献   

6.
反相高效液相色谱法同时测定三七药材中4种皂苷的含量   总被引:9,自引:0,他引:9  
建立了以0.02%磷酸-乙腈为流动相,梯度洗脱反相高效液相色谱同时测定中药材三七中三七皂苷R1、人参皂苷Rg1、Rb1和Rd 4种皂苷的新方法。R1、Rg1、Rb1和Rd 4种皂苷的加样回收率分别为89.54%、90.08%、82.82%与84.46%;线性范围分别为0.244-6.110、0.820-20.510、0.396-9.890与0.260-6.500μg。测定了不同规格、部位和来源的三七药材里的4种皂苷R1、Rg1、Rb1和Rd。方法准确可靠,结果稳定,重现性好,可用于三七及其制剂的质控。  相似文献   

7.
血清游离羟脯氨酸的快速检测   总被引:7,自引:0,他引:7  
采用6300黄金系统氨基酸分析仪,在锂柱140min程序生理体液分析方法基础上,建立了血清游离羟脯氨酸(HYP)快速测定方法,并用该法检测了正常人及肾病(有或无肾小铧与肾间质纤维化)病人血清中游离HYP的含量;用该法完成分析的时间为24min,比原方法缩短了116min;该法重复性良好,日内RSD2.3%,日间RSD3.7%,回收率97%;纤维化组血清羟脯氨酸浓度显著高于无纤维化组(P<0.001)和健康对照组(P<0.001),用该指标显著增高判断肾纤维化,敏感性100%,特异性915,假阳性9%;该法是一种快速、准确、可靠的血清因浆羟脯氨酸定量检测方法,有利于大批量样品的快速测定,并可为临床判断肾病病人肾纤维化提供辅助诊断指标。  相似文献   

8.
卫艳丽  董川等 《分析化学》2002,30(3):301-303
以快速定量滤纸为基质,用KI-NaAc为重原子微扰剂,建立了测定痕量可可碱、咖啡因、茶碱的滤纸基质室温Lin光(PS-RTP)分析法。该法取样量少,线性范围宽,可可碱、咖啡因、茶碱的线性范围分别为14.4-576;5.44-699;7.21-360ng/斑点;检出限分别为1.14、0.78、1.80ng/斑点。该方法用于巧克力中可可碱、茶叶中咖啡因、氨茶碱药片中茶碱的测定,操作简便快速,选择性好。标准回收率在92.8%-106%之间;相对标准偏差RSD<5%。  相似文献   

9.
9种人参皂苷同时测定方法及在人参质量鉴别中的应用   总被引:1,自引:0,他引:1  
潘坚扬  程翼宇  王毅  肖新月  林瑞超 《分析化学》2005,33(11):1565-1568
建立可同时测定人参皂苷Rg1、Re、Rf、Rg2、Rb1、Re、Rb2、Rb3和Rd含量的反相高效液相色谱(RP—HPLC)方法。采用Agilent Zorbax SB-C18柱,以乙腈-水-0.05%磷酸为流动相,流速1.5mlMmin,柱温35℃,检测波长203nm。在此色谱条件下,各组分在60min内均得到较好分离,回收率符合含量测定要求。运用该方法对不同产地人参进行含量测定,道地药材主根中9种人参皂苷总含量为1.19—1.45%,须根为5.47—6.90%,3个非道地药材主根分别为1.03%、1.04%、1.85%。聚类分析结果表明,根据测定的9种皂苷含量能准确区分人参的主根与须根,并判断其道地性。  相似文献   

10.
新疆榅桲中总皂苷的光度测定   总被引:1,自引:0,他引:1  
采用分光光度法对榅桲中的皂苷成分进行研究,测定了榅桲中的总皂苷,回归方程为y=0.1028 2.17ρ,r=0.9973,七叶苷标准溶液在0.094~0.564 mg/mL范围内有很好的线性关系。用正交设计法优化了实验条件。回收率为80%~94%。  相似文献   

11.
用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.  相似文献   

12.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

13.
The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.  相似文献   

14.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

15.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

16.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

17.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.  相似文献   

18.
19.
《Tetrahedron》2014,70(21):3377-3384
The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.  相似文献   

20.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

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