圆萼刺参中的芦丁,熊果酸和齐墩果酸的定性定量分析

采用薄层色谱法(TLC)和反相高效液相色谱法(RP-HPLC)对藏药材圆萼刺参中的芦丁,熊果酸和齐墩果酸进行定性和定量的分析。定性分析:TLC法检定芦丁和熊果酸和齐墩果酸成分,薄层色谱条件是以V(乙酸乙酯)∶V(丁酮)∶V(甲酸)∶V(水)=10∶6∶1∶2为展开剂,喷以10 g/L NaNO2的1%甲醇溶液在105℃检定芦丁,以V(CHCl3)∶V(乙酸乙酯)=1∶1为展开剂,喷以V(H2SO4)∶V(甲醇)=1∶2溶液在105℃检定熊果酸和齐墩果酸。定量分析:RP-HPLC法测定圆萼刺参中芦丁,流动相:V(甲醇)∶V(0.4%H3PO4溶液)=38∶62;检测波长340 nm;RP-HPLC法测定熊果酸和齐墩果酸,流动相:V(甲醇)∶V(0.2%H3PO4)溶液=85∶15;检测波长215 nm;圆萼刺参中的齐墩果酸,在本种植物中首次发现。     

应用色谱/质谱联用方法分析霉菌单加氧酶羟基化齐墩果酸体系

用反相高效液相色谱法/质谱法对天然药物齐墩果酸及其以霉菌的P450酶系作为生物催化剂的齐墩果酸羟化体系中齐墩果酸和羟化齐墩果酸进行分离分析.方法选用Lichrospher C18柱,以乙腈-水为流动相,进行梯度洗脱,用二极管阵列检测器(DAD)和电喷雾质谱(ESI-MS)为检测手段,通过色谱图和对应质谱图,确定了齐墩果酸及其羟化产物的色谱行为,建立了HPLC/DAD/ESI-MS联用法分离鉴定齐墩果酸及羟化产物的快速有效的方法.     

藏药花锚中齐墩果酸和熊果酸含量测定

用薄层色谱法和反相高效液相色谱法对青海两地区野生椭圆叶花锚中齐墩果酸和熊果酸进行定性定量分析。采用超声法提取椭圆叶花锚中的齐墩果酸和熊果酸,并采用反相高效液相色谱法测定其含量。测得青沙山地区花锚中齐墩果酸和熊果酸含量均高于大通宝库乡产地,两产地花锚中熊果酸含量均高于齐墩果酸含量。     

反相高效液相色谱法测定啤酒中的酚酸

建立了一种利用反相高效液相色谱法同时测定啤酒中10种酚酸的方法。没食子酸、原儿茶酸、儿茶素、香草酸、咖啡酸、丁香酸、表儿茶素、p-香豆酸、阿魏酸和槲皮素等在色谱柱Zorbax Eclipse XDB-C18(4.6 mm i.d.×250mm,5μm),流动相为甲醇/水(含0.1%醋酸),梯度洗脱,流速为1.0 mL/min,280和254 nm紫外检测,除表儿茶素(61.34%)外加标回收率都在96%~130%之间,RSD<5%。该方法可以简便、准确地测定啤酒中的酚酸。     

熊果酸与齐墩果酸高效液相色谱分离条件优化

描述了熊果酸、齐墩果酸色谱保留行为与流动相pH和有机溶剂体积分数之间的函数关系,并求解了各自模型中的9个参数,得到在流动相中熊果酸的电离常数pKa=4.8145,齐墩果酸电离常数pKa=4.9317。文章还对模型外推过程中存在的误差进行了校正,并运用校正后的模型预测熊果酸的容量因子,实验值接近预测值,误差小于5%。最后采用熊果酸和齐墩果酸的容量因子与流动相pH和有机溶剂组成之间的函数关系,进行了两者在同一流动相中分离条件的优化,获得了最佳的分离条件:流动相中甲醇体积分数为85.2%,pH为6.50。     

化学衍生辅助液相色谱-串联质谱测定枇杷膏中的齐墩果酸和熊果酸

建立了一种液相色谱-串联质谱(LC-MS/MS)同时测定齐墩果酸和熊果酸含量的分析方法,利用衍生化试剂N,N-二甲基乙二胺(DMED)和d4-N,N-二甲基乙二胺(d4-DMED)分别衍生样品和标准工作溶液中的目标分析物,并将标准工作液的衍生产物作为稳定同位素内标。该方法线性关系良好,相关系数均0.99;齐墩果酸和熊果酸的检出限(S/N=3)分别为0.92 ng/L和1.06 ng/L,加标回收率分别为98.7%~102.7%和97.2%~105.0%。该方法简单、快速、准确,可满足枇杷膏中齐墩果酸和熊果酸高灵敏度检测的需求。     

茶条木挥发油的化学成分

采用毛细管气相色谱－质谱联用法对茶条木挥发油化学成分进行了研究,经毛细管普分离出１３４个峰,共确认了其中１０１种成分,所鉴定化合物的含量占全油的７８．０８％。用气相色谱面积归一化法测定了各成分的相对含量,其主要化学成分为二苯胺、棕榈酸甲酯、十六酸等。     

高效液相色谱法同时测定苹果汁中6种酚类物质

建立了同时测定苹果汁中儿茶素、绿原酸、咖啡酸、表儿茶素、香豆酸和阿魏酸6种酚类物质的反相高效液相色谱方法,并对酚类物质的稳定性进行了探讨。选用Eclipse XDB-C18色谱柱(150 mm×4.6 mmi.d,5μm),以甲醇-1%乙酸水溶液作为流动相进行梯度洗脱。柱温30℃,流速1.0 mL/min,在280 nm波长下进行检测。本方法样品处理简单,具有良好的重现性和线性,相关性系数均达到0.9999,儿茶素、绿原酸、咖啡酸、表儿茶素和香豆酸和阿魏酸的回收率分别为102%~103%、94.3%~101%、102%~104%、98.4%~101%、96.2%~99.8%和102%~104%;检出限分别为20、30、10、20、7和15μg/L(S/N=3)。     

腺叶蔷薇果实化学成分的HPLC-MS分析

蔷薇属植物广泛分布于世界各地,在我国有80余种,其中许多具有药用价值。该属植物的叶片和果实中含有槲皮素、山奈酚、芦丁等多种黄酮类化合物和齐墩果酸、乌苏酸等三萜化合物。腺叶蔷薇(RosakokanicaRegelexJuzep)主要分布于新疆,生长在海拔1500-2500m的山坡及林缘,其果实具有活血化淤、去风除湿和解毒收敛的功效。由于该植物果实的化学成分还未见报道,我们利用高效液相色谱-电喷雾串联质谱对其提取物进行分析,从所获得的紫外和质谱信息,并参考与之生源相近的同属其它植物化学成分研究的结果,初步鉴定出5个主要的化学成分。     

UPLC-MS/MS法测定中药材中齐墩果酸与熊果酸的含量

建立了一种同时检测中药材中齐墩果酸(OA)和熊果酸(UA)含量的超高效液相色谱串联质谱方法。采用超高效液相色谱-三级四极杆质谱(UPLC-TQMS)法对样品进行测定,Waters Acquity UPLC BEH C_(18)色谱柱(50 mm×2.1 mm,1.7μm)进行分离,以乙腈-5 mmol/L乙酸铵水溶液(氨水调至pH 9.24)为流动相,梯度洗脱;负离子模式下检测。结果表明,齐墩果酸和熊果酸在0.5~50.0 ng/mL浓度范围内线性关系良好,相关系数(r~2)分别为0.999 8和0.999 7;检出限(S/N=3)分别为0.006 6,0.012 8 ng/mL,定量下限(S/N=10)分别为0.002 0,0.003 8 ng/mL;对OA和UA进行加标回收实验,平均回收率分别为101.1%和100.8%,相对标准偏差(RSD,n=9)分别为1.8%和0.04%。对10种不同中药材中齐墩果酸和熊果酸含量进行检测,结果表明该方法快速简便、准确度高、重现性好,可用于含有齐墩果酸和熊果酸的中药材含量测定。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Effect of the Method of Modification of Zeolite X on Selectivity of Catalytic Methylation of Toluene

Theoretical and Experimental Chemistry - The effect of the method of modification of catalysts based on zeolite X by cesium and magnesium cations (ion exchange and impregnation) on the selectivity...     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Synthesis of tetrabenzoporphins of the basis of isoindoline

Chemistry of Heterocyclic Compounds -