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1.
建立了毛细管电泳法测定中药复方制剂双黄连口恨液中黄芩甙元、黄芩甙、绿原酸和咖啡酸的方法,通过研究缓冲溶液pH和浓度、分离电压、进样时间和有饥添加剂的影响优化了分析条件在优化的条件下,20min内实现了4种物质的良好分离黄芩甙元、黄芩甙、绿原酸和咖啡酸峰高和质量浓度分别在0.05~1.50、0.06~1.20、0.02~0.50和0.02~0.50g/L范围内呈良好线性;俭出限分别为0.015、0.020、0.004、0.004g/L基于迁移时间和峰高的重复性分别为:黄芩甙元,1.70%和3.94%;黄芩甙,1.60%和3.63%;绿原酸,1.60%和2.05%;咖啡酸,1.51%和2.83%通过分析实际样品并做加标回收实验验证了该方法的可行性。  相似文献   

2.
毛细管电泳法测定复方鱼腥草片中的绿原酸和槲皮素   总被引:8,自引:2,他引:6  
建立了毛细管电泳法分析复方鱼腥草片中绿原酸和槲皮素的方法,通过研究缓冲溶液酸度和浓度、工作电压和进样时间的影响优化了分析条件。在优化的条件下,15min内实现了两种分析物质的良好分离。绿原酸和槲皮素峰高和质量浓度分别在0.05~0.80g/L和0.05~1.00g/L范围内成良好线性。基于迁移时间和峰高的重复性(RSD)分别为:绿原酸,1.91%和4.32%;槲皮素,2.30%和3.18%。绿原酸和槲皮素的检出限(S/N=3)分别为0.014g/L和0.015g/L。通过分析实际样品并做加样回收实验进一步验证了该方法的可行性。  相似文献   

3.
应用冷原子吸收光谱法测定化妆品中痕量汞,在所选最佳测定条件下,测得方法的检出限为0.1μg·kg-1,测定下限为0.40 mg·kg-1,取4.0μg·L-1汞标液作精密度试验,算得相对标准偏差为0.6%,用标准加入法作回收率试验,所得结果在92%~97%之间。  相似文献   

4.
痕量铈的催化动力学光度法测定   总被引:3,自引:0,他引:3  
基于pH 9.0的氨水-氯化铵缓冲溶液中,痕量铈(Ⅳ)对溴酸钾氧化溴甲酚紫褪色的指示反应有明显的催化作用。据此建立了痕量铈(IV)的光度测定法,铈量在0~4.0μg·L-1间与△A值间呈线性关系,检出限为0.092μg·L-1。用于测定人发、茶叶和大米样品中痕量铈(IV),结果的相对标准偏差在3.6%~5.4%之间,回收率在96%~103%之间。  相似文献   

5.
谷氨酸的硫化锌法原子吸收光谱间接测定   总被引:6,自引:0,他引:6  
利用ZnS悬浮液与谷氨酸在碱性条件下生成可溶性谷氨酸锌络合物 ,研究了塞曼原子吸收间接测定谷氨酸的方法 ;谷氨酸测定的质量浓度线性范围为0~3g·L-1,特征质量浓度为27.3mg·L-1;该法可用于调味品中的谷氨酸或谷氨酸钠的测定 ,其相对标准偏差为0.4 %(n=7) ,方法的回收率在97 %~103%之间  相似文献   

6.
采用微波制样技术,用石墨炉原子吸收光谱法测定水产品中痕量铍。方法的线性范围为0-10μg·L-1,检出限为0.076 ng·g-1,相对标准偏差为2.7%,回收率为97.0%。方法准确、快速、简便,并与常压消解法的结果比较,基本一致,已用于水产品中痕量铍的测定。  相似文献   

7.
银黄冲剂中黄芩甙和绿原酸的毛细管电泳分离分析   总被引:8,自引:0,他引:8  
杨新  韩凤梅  程智勇  陈勇 《色谱》1999,17(6):573-575
摘要:用毛细管电泳法分离并测定了银黄冲剂中黄芩甙和绿原酸。以对硝基苯甲酸为内标,未涂层融硅毛细管(50μmi.d.,370μmo.d.,总长47cm,有效分离长度40cm)为分离通道,25mmol/L硼砂缓冲液(pH8.5)为电泳介质,17kPa·s压力进样,25kV恒压电泳,310nm检测。黄芩甙和绿原酸线性范围分别为160~960mg/L(r=0.9993,RSD=1.76%~2.33%)和80~960mg/L(r=0.9989,RSD=1.07%~2.51%),加入回收率:黄芩甙为(102.09±1  相似文献   

8.
通过优化缓冲溶液pH和浓度、SDS浓度和β-CD等条件,建立了一种HP-β-CD毛细管胶束电动色谱法测定密蒙花中的芹菜素和木犀草素的方法。在优化的条件下,2种物质在15min内得到良好分离。木犀草素和芹菜素的峰高和浓度在0.01—0.60g/L范围内成良好线性。2种物质基于迁移时间和峰高的相对标准偏差分别为1.2%、1.9%和2.5%、2.8%。检出限分别为0.005和0.0045g/L。  相似文献   

9.
采用高效毛细管电泳-电化学检测法同时测定复方维生素B片中的主要成分维生素B1,B12,B6和C的含量;研究了电极电位,运行缓冲溶液的浓度和酸度,电泳电压和进样时间等对电泳的影响,以微铂电极为工作电极,检测电位+0.5V(vs SCE),在pH9.0的15mmol/L Tris-1mmol/L H3BO3缓冲溶液中,上述4组分在5min内获得基线分离;维生素B1,B12,B6和C的线性范围分别为2.1mg/L-1.0g/L,6.0mg/L-0.80g/L,1.4mg/L-0.72g/L和0.97mg/L-0.44g/L检出限分别为0.50mg/L,1.0mg/L,,0.65mg/L和0.40mg/L;5次测定峰高的相对标准偏差分别为2.4%,3.0%,3.1%,和2.5%,5次测定的平均回收率分别为99%,102%,98%和100%。  相似文献   

10.
用毛细管区带电泳 -电化学检测法测定了黄芩及其制剂中黄芩素和黄芩甙的含量。研究了电极电位、电解液酸度和浓度、电泳电压及进样时间等对电泳的影响 ,得到了较为优化的测定条件。以直径为300μm的碳圆盘电极为检测电极 ,电极电位为0.90V(vsSCE) ,在100mmol/L硼酸盐缓冲液(pH9.0)中 ,上述两组分在8min内完全分离。黄芩素和黄芩甙浓度与电泳峰电流分别在5.0×10 -7~1.0×10 -3mol/L和1.0×10 -6~1.0×10 -3mol/L范围内呈良好线性 ,检出限分别为2.24×10 -7mol/L和5.48×10 -7mol/L。7次测定分别含5.0×10 -4mol/L黄芩素和黄芩甙试样溶液 ,峰高的相对标准偏差分别为3.53%和4.03%。  相似文献   

11.
12.
Abstract

2-(Thiocyanatoacetyl)thiophene 2 and its selenium analog 3 couple with diazotized anilines and yield 3-aryl-2-imino-5-(2-thenoyl)-2,3-dihydro-1,3,4-thiadiazoles 6 and 3-aryl-2-imino-5-(2-thenoyl)-2,3-dihydro-1,3,4-selenadiazoles 7 respectively. The reactions of both 6 and 7 with nitrous acid, acetic anhydride and benzoyl chloride are described. Azo coupling of 2-amino-4-(2-thienyl)thiazole 17 and its selenazole analog 18 with diazotized anilines yielded the arylazo derivatives 19 and 20 respectively. Reaction of the hydrazidoyl bromide 16 with potassium thiocyanate, potassium selenocyanate, thiourea and selenourea yields 6, 7, 19, and 20 respectively.  相似文献   

13.
PHOTOLYSIS AND RADIOLYSIS OF NITROMETHANE AND NITROETHANE   总被引:1,自引:0,他引:1  
Abstract— Prolonged photolysis of nitromethane and nitroethane in liquid and vapour phases, with simultaneous photolysis of the nitrogen dioxide formed, was studied in the absence and presence of cupric oxide. A high-pressure quartz immersion lamp providing the full range of visible and u.v. spectrum, with a high output of radiation at 366 and 313 mμ, was employed as source of light. The products of photolysis were detected by microanalytical methods, infrared-absorption spectrum analysis and gas chromatography. Photolysis of liquid nitro-alkanes resulted in formation of many compounds; saturated hydrocarbons, and in the case of nitroethane, ethylene, were submitted to detailed examination. Photolysis in the vapour phase was carried out in a specially designed glass apparatus. The main products were nitrogen dioxide, aldehydes and polyaldehydes; hydrocarbons were not estimated.
Liquid nitromethane and nitroethane were also irradiated with γ-rays from a 60Co source. The radiolysis products were similiar to those obtained on photolysis. The mechanism of photolytic decomposition of nitroalkanes is proposed and discussed.  相似文献   

14.
9-氨基壬酸系从癸二酸经单酯化、氨化和Hofmann重排制得。该单体以10克规模在玻璃管中和以4公斤量在15升聚合釜中,于260℃聚合成聚壬酰胺。聚合物在288℃纺丝,120℃牵伸,得到尼龙-9纤维。测定了聚合物和纤维的结构和多种性能。  相似文献   

15.
用顺丁烯二酸酐 (MAH)对具有分子包结能力的 β 环糊精 (β CD)进行化学改性 ,合成出了丁烯二酸单酯化 β CD单体 (MAH β CD) .通过氧化还原自由基引发MAH β CD与N 异丙基丙烯酰胺 (NIPA)聚合 ,合成出含 β CD结构单元的新型水凝胶 .用核磁共振、红外光谱及元素分析对MAH β CD单体及共聚物的结构和组成进行了表征 .溶胀研究结果表明 ,该水凝胶具有较好的pH、温度及离子强度敏感性 ;并且水凝胶在较高羧基(—COOH)含量和弱碱环境中 ,仍能表现出明显的温敏性  相似文献   

16.
Abstract— The spectra of absorption, fluorescence and excitation of monolayers and thin films containing chlorophyll a together with a carotenoid (cis-β-carotene, trans-β-carotene, fucoxanthin, or zeaxanthin), were measured at — 196°C. The concentration ratios used, (Chl)/(Car), were 6:1, 4:1, 3:1, 2:1, 1:1 and 1:3, and the area densities, 3·70, 2·55, 1·76, 0·71, 0·37 and 0·17 nm2/pigment molecule. In dilute monolayers, (3·70 nm2/molecule), with a constant concentration ratio (Chl)/(Car) = 3:1, evidence of three β-carotene forms, with absorption bands at 460, 500 and 520 nm (C460, C500 and C520), and of a chlorophyll a form with an absorption band at 669–672 (Chl669–672) was found. On increasing the density to 0·2–0·3 nm2/molecule, a conversion of C460 and C520 into C500, was observed, and several more additional (probably more strongly aggregated) chlorophyll a forms appeared, with absorption bands at 672–733 nm. With excess carotene [(Chi)/(Car) = 1:3] the forms C460, C500, C520 and Chl669–672 were present even in the most dense films (0·2–0·3 nm2/molecule). The same was found with other carotenoids: if one of the pigments was in excess, aggregated forms of the other tended to disappear. In the transfer of energy from carotenoids to chlorophyll a, C500 was found to be the main donor. In layers with a concentration ratio (Chl)/(Car) = 3:1, the efficiency of transfer was less than 10 per cent at the lowest density used (3·70 nm2/molecule); it increased to 50 per cent, as the density was increased to 0·20 nm2/molecule. When the relative concentration of the carotenoid was increased to (Chl)/(Car) = 1:1, the efficiency of energy transfer dropped to 25 per cent even at 0·20 nm2/molecule. It seems that the efficiency of energy transfer between carotene molecules (prior to its transfer to chlorophyll a) is low, and effective transfer occurs only between β-carotene and immediately adjacent chlorophyll a molecules.  相似文献   

17.
生物质热解、加氢热解及其与煤共热解的热重研究   总被引:36,自引:3,他引:36  
在加压热天平上用非等温热重法进行生物质(锯末、稻壳)在N2气氛下的热解和加氢热解研究。考察了升温速率(5~25℃/min)和压力(0.1~7MPa)的影响,求取了热解动力学参数,并研究了生物质与煤在常压N2气下的共热解过程。研究结果表明:生物质在400℃左右即完成热解反应,总失重率大于70%(W%,daf.),热解时仅一个峰位于300℃左右;与煤热解行为相同,随升温速率及压力的升高,转化率下降,DTG峰移向高温,但由于热解反应在较低温度下进行,氧气的存在对生物质热解TG和DTG的影响远小于煤热解。证明生物质热解以其内部氢对自由基的饱和及分子重排反应为主。生物质热解可用一级反应动力学处理,主要热解阶段及表现活化能分别为:锯末,267~314℃,69.66kJ/mol;稻壳,283~310℃,53.45kJ/mol;生物质由于与煤的热分解温度相差很大,因而在其共热解过程中无协同作用。  相似文献   

18.
The attractive Interactions between typically hydrophobic molecules such as hexane or CCl4, and the repulsive Interactions between extremely hydrophilic molecules such as poly(ethylene oxide) (PEO), when immersed in water, as well as the interactions between these molecules and water, have been examined from a surface thermodynamic viewpoint, taking the changes in surface free energy into account, as a function of temperature. It was found that attractive hydrophobic Interactions are not, as vas generally believed up to now, invariably entropic. Hydrophobic Interactions can be mainly enthalpic or mainly entropic, or more or less equal mixtures of both, depending on each individual case; however, all hydrophobic interactions are polar (in the sense of Lewis acid-base) in nature. Repulsive hydrophilic interactions are enthalpic, and also polar in nature. The interaction between hydrophobic solutes and water is mainly enthalpic, and is apolar in nature.  相似文献   

19.
Conchostracans, with a laterally compressed body enclosed between two symmetric valves, live swimming in fresh or brackish water. The carapace valve has a number of growth bands with various sculptures. The general trend of sculptural evolution is from smooth to punctate-minute polygon-medium reticulation-large reticulation, while these punctate, polygonal and various reticulate patterns may separately develop into various radial ridges. The development of sculpture can be well explained by mechanical principle. Functional morphology of carapace is discussed in the light of mechanics in this paper.  相似文献   

20.
本文报道了四个N-酰基硫脲衍生物及其Cu^2+,Ni^2+,Cd^2+,Sn^4+配合物的合成。用质谱、红外光谱、紫外光谱对它们进行了结构、性质表征。配体与金属离子配位主要是通过硫原子进行,配合物都是非离子型的。  相似文献   

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