溪黄草及其不同提取物的红外光谱研究

采用一维红外光谱、二阶导数谱和二维相关红外光谱对溪黄草原药材及其不同溶剂提取物进行了红外光谱研究。结果表明:溪黄草原药材中含有酯类、芳香类和糖苷类等物质,溪黄草水提物中主要为糖类物质,乙醇提取物中主要为黄酮类物质,石油醚提取物中主要为酯类物质。红外光谱能够快速、简便地提供中药及其提取物中主要化学成分的宏观信息,从而为后续的化学成分分析和中药提取分离方法的改进和优化提供有效参考。     

近红外光谱在蛋白质和含酰胺基团聚合物研究中的应用

近红外光谱(near-infrared spectroscopy,NIR)是一种常用的无损表征手段,但谱带强度弱、交叠情况严重等缺点局限了它的应用范围。本文介绍了几种常见的改善近红外光谱技术不足的方法,如二阶导数法、二维相关光谱法和化学计量法等,并举例阐述了近红外光谱在蛋白质和含酰胺基团聚合物的结构和含量等方面的应用。这些方法对近红外光谱的定性定量分析起了很好的辅助作用,有效地拓宽了近红外光谱技术的应用领域。     

松杉灵芝不同部位的红外光谱分析研究

采用红外光谱三级鉴定法对松杉灵芝菌盖、表皮、菌柄、子实体不同部位的红外光谱图进行了整体分析。结果表明:松杉灵芝的各部位均含萜类、甾醇类、氨基酸、多肽、蛋白质和糖苷类等物质。在松杉灵芝的一维红外光谱中,菌盖的1 649cm-1峰的相对强度明显比表皮、菌柄和子实体强,说明菌盖中所含的氨基酸、多肽、蛋白质物质的量比其它部位高;在二阶导数谱中,四者在1 720~1 600cm-1范围内峰形差别较大,进一步说明松杉灵芝不同部位所含氨基酸、多肽、蛋白质物质不一致;而二维相关红外光谱中,各部位自动峰的数目、峰位置和峰相对强度都有所不同,可推断松杉灵芝各部位本身所含的糖苷类物质是不一致的。     

不同产地黄芪的红外光谱鉴别研究

采用红外光谱、二阶导数红外光谱和二维相关红外光谱,对四种不同产地的黄芪原药材进行了鉴别研究。结果表明:不同产地黄芪的红外光谱和二阶导数红外谱具有一定的相似度,与淀粉的红外谱图比对,4个不同产地的黄芪均含有淀粉,其中陕西绥德产黄芪的淀粉含量比其它3个产地黄芪的都要高。山西浑源和山西天镇产黄芪谱图的1 510、1 425cm-1木质素特征峰比内蒙古固阳和陕西绥德产黄芪的更为明显,说明前二者产黄芪中木质素含量高于后二者产黄芪。在二维相关红外谱图上,根据4个产地黄芪的相对峰强度的差异,可进行产地的鉴别。研究结果表明对于不同产地黄芪的鉴别,红外三级鉴定法是一种快速有效的新方法。     

变温傅里叶红外光谱技术研究硬脂酸C-H伸缩振动

采用傅里叶红外光谱技术研究了温度对于硬脂酸C-H伸缩振动、分子脂肪链构象改变和分子间作用力的影响。运用变温红外技术在293~393K范围内,分别测定了硬脂酸C-H的一维红外光谱、二阶导数红外光谱、四阶导数红外光谱和去卷积红外光谱。结果表明:1在293~333K范围内,一维红外光谱中2 965,2 870cm-1附近的弱吸收谱带分别归属于甲基的不对称伸缩振动模式νas(-CH3)和对称伸缩振动模式νs(-CH3),相应的导数光谱及去卷积红外光谱能提高一维红外谱的分辨率;2在293~333K范围内,硬脂酸脂肪链处于全反式构象,在348~353K范围内,硬脂酸分子脂肪链构象由全反式构象向无序构象转变;3随着测量温度的升高,硬脂酸分子间的作用力不断降低。     

蒙药草乌花及其提取物化学成分的红外光谱法整体结构解析

采用傅立叶变换红外光谱法并借助于二阶导数谱以及二维相关红外光谱(2D-FTIR)研究了蒙药草乌花原药材及不同溶剂提取物(依次采用乙醚,乙醇和水提取)所含化学成分的红外谱图整体变化规律.结果显示:在草乌花原药材中具有明显的多糖类化合物的红外特征吸收峰,证明该药材中含有大量多糖类成分.草乌花药材乙醚和醇提物的红外光谱较相似...     

红外二阶导数指纹图谱用于紫花地丁药材的产地分类

建立了紫花地丁药材的红外二阶导数指纹图谱。采用傅里叶变换-红外光谱法测定10个不同产地紫花地丁试样的红外光谱,红外分辨率为8 cm-1,扫描范围为4 000~400 cm-1,利用二阶导数重构指纹图谱后,进行系统聚类分析和Fisher′s判别分析。结果表明所建立的方法能够能有效地对样品产地进行预测,可为紫花地丁药材质量控制提供一种简便、有效的手段。     

红外光谱法分析酵母蛋白质的二级结构

采用红外光谱法分析了酵母蛋白质的二级结构。测定了不同温度下酵母酰胺Ⅲ带的一维红外光谱、二阶导数红外光谱及去卷积红外光谱。结果表明:随着测量温度的升高,酵母中的蛋白质α-螺旋结构的红外吸收强度降低;而β-转角结构、无规卷曲结构和β-折叠结构红外吸收强度均有所增加。还研究了酵母酰胺Ⅲ带的二维红外光谱,以确定酵母中蛋白质红外吸收强度的变化次序,进一步证明了酵母蛋白质的β-折叠结构的热不稳定性。     

导数技术在植物叶片荧光研究中的应用

本文首次采用导数技术于植物叶片的活体叶绿素荧光性质研究,探讨了其生物学意义。该方法降低了不同叶绿素存在形式光谱干扰程度,提高了谱带分辩率。衰老期植物叶片的导数荧光光谱和常规荧光光谱相比,对叶衰老的敏感程度增加,导数技术的应用便于植物状态的评估。     

变温傅里叶红外光谱技术研究硬脂酸结构及相变机理

采用傅里叶红外光谱法研究了温度对于硬脂酸分子结构影响。通过变温红外技术在293~393K范围内,分别测定了硬脂酸羰基的傅里叶红外光谱、二阶导数红外光谱及去卷积红外光谱。结果表明,硬脂酸主要存在反式二聚体1、顺式二聚体2、开环二聚体3及单体4等4种结构。     

苯并卟啉羟基和醚类衍生物的简便合成

以原卟啉IX二甲酯(1)为起始原料,简便地合成了四种位置异构体苯并卟啉羟基及醚类衍生物:3-甲氧乙基苯并卟啉衍生物16,3-羟乙基苯并卟啉衍生物17,8-甲氧乙基苯并卟啉衍生物20和8-羟乙基苯并卟啉衍生物21。     

Simultaneous Determination of Perphenazine and Amitriptyline by Derivative Spectrophotometry

Abstract

Two methods have been developed for the simultaneous determination of Amitryptiline and Perphenazine: the zero-crossing (I) and the derivative ratio spectrum (II) methods and both use the derivative spectrophotometry.

The methods have been applicable in the ranges of 1 to 30 μg·ml^?1 of Amitryptiline (I and II) and between 1 and 8 μg·ml^?1 and from 1 to 7 μg·ml^?1 of Perphenazine for the methods I and II respectively. The accuracy of the proposed methods have been studied and they have been used in the determination of Amitryptiline and Perphenazine in commercially available pharmaceuticals.     

Application of Difference and Derivative Ultraviolet Spectrometry for the Assay of Some Benzodiazepines

Abstract

Differential (δ A), second derivative (D₂) and differential second derivative (δ D₂) ultraviolet spectrophotometric methods have been described for the quantitiative estimation of clonazepam, diazepam and medazepam in pharmaceutical formulations such as drops, tablets and capsules. Interferences due to excipients and diluents are thereby avoided. Accuracy of the analyses with the proposed procedures is significantly greater than the conventional spectrophotometric and official methods.     

烟草萃取物中烟碱和苯的紫外导数光谱测定

定量分析烟碱有多种方法,常用者为水蒸汽蒸馏比色法、薄层色谱、高压液相色谱和极谱法等。在以苯作为萃取剂制取纯烟碱的过程中,采用了水浸、过滤、沉淀、萃取、蒸馏等工序,使烟碱与其它成分分离。由于烟碱易溶于苯,蒸馏后还残留有部分苯。苯和烟     

吡唑啉衍生物与溶剂相互作用的研究

通过对一类吡唑啉衍生物（1-苯基-3-（N，N-二甲基氨基苯乙烯）-5-（4-N，N-二甲基氨基苯基）-2-吡唑啉）在不同溶剂中的光谱行为，研究了该衍生物和溶剂分子间的一般相互作用和特殊相互作用．发现利用吡唑啉溶液的荧光猝灭现象能对其和溶剂分子间不同相互作用问题提供有价值的信息．     

Wavelet Derivative: Application in Multicomponent Analysis of Electrochemical Signals

The wavelet derivative was developed for resolving overlapped signals in electrochemical analysis. It has been shown that the wavelet derivative could be used as an effective tool in resolution enhancement of the electrochemical signals. Since signal‐to‐noise ratio (SNR) does not degrade significantly at high order derivatives, the wavelet derivative is much better than the conventional numerical derivative in resolving practical signals with low SNR, particularly in the case when the overlapped degree of complex is high and high order derivatives are required for the further resolution enhancement. In this article, applications of the wavelet derivative in the voltammetric determination of small mounts of substances in the presence of large mounts of potentially interfering species are presented, and the advantages of this technique are discussed as well.     

Electroanalytical Studies and Simultaneous Determination of Amlodipine Besylate and Atorvastatine Calcium in Binary Mixtures Using First Derivative of the Ratio‐Voltammetric Methods

The electrochemical behavior of atorvastatin and amlodipine at a glassy carbon electrode has been studied using different voltammetric techniques. First derivative of the ratio voltammetric methods for determination of amlodipine and atorvastatin in tablets in the presence of the other compound has been described. This technique depends on the measuring of first derivative of the ratio voltammograms of each concentration as a function of the increased concentrations. DP and SW voltammetric methods depend on first derivative of the ratio‐voltammetry by measurements of the selected potentials for amlodipine and atorvastatin. The linear response was within the range of 4×10^?6–1×10^?4 M for amlodipine and 2×10^?6–1×10^?4 M for atorvastatin. The proposed methods have been extensively validated.     

The mathematics of functional differentiation under conservation constraint

The mathematics of K-conserving functional differentiation, with K being the integral of some invertible function of the functional variable, is clarified. The most general form for constrained functional derivatives is derived from the requirement that two functionals that are equal over a restricted domain have equal derivatives over that domain. It is shown that the K-conserving derivative formula is the one that yields no effect of K-conservation on the differentiation of K-independent functionals, which gives the basis for its generalization for multiple constraints. Connections with the derivative with respect to the shape of the functional variable and with the shape-conserving derivative, together with their use in the density-functional theory of many-electron systems, are discussed. Yielding an intuitive interpretation of K- conserving functional derivatives, it is also shown that K-conserving derivatives emerge as directional derivatives along K-conserving paths, which is achieved via a generalization of the Gateaux derivative for that kind of paths. These results constitute the background for the practical application of K-conserving differentiation.      

Third Derivative Spectrophotometric Determination of Metomidate from Aqueous Solution

Abstract

The third derivative spectrophotometric method has been proposed for the determination of metomidate from aqueous solution. By hydrolysis of metomidate, D,L-l-(l-phenylethyl)-imidazole-5-carboxylic acid is formed. Determining the absolute value of the third derivative spectra in the “zero-crossing” point, the concentration of metomidate can be calculated directly without any interferences. The validity of the method was confirmed using synthetic mixtures. Kinetic investigation of the degradation rate of metomidate revealed that the proposed method is stability indicating.     

Simultaneous Determination of Cobalt and Nickel Using Morpholinedithiocarbamate (MDTC) as Reagent by First and Second Derivative Spectrophotometry

A selective and sensitive derivative method has been proposed for the simultaneous determination of trace amounts of Co(II) and Ni(II) with morpholinedithiocarbamate (MDTC) in the presence of sodium lauryl sulphate (SLS). The molar absorption coefficients of the 1:2 complex of Co(II) and Ni(II) at 326 nm and 322 nm are 2.248 × 10⁴ and 2.505 × 10⁴ L mol^?1 cm^?1 for zero order. The analytical sensitivity for the second derivative of Co(II) and Ni(II) complexes are 0.0044 μg mL^?1 and 0.0060 μg mL^?1. The developed derivative procedure, using the zero‐crossing technique, has been successfully applied for the analysis of Co(II) and Ni(II) simultaneously in different alloy samples.