共查询到20条相似文献,搜索用时 250 毫秒
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高效液相色谱/电喷雾质谱测定减肥保健品中的盐酸西布曲明 总被引:2,自引:0,他引:2
盐酸西布曲明为减肥处方药,禁止添加到保健食品中;探索了利用高效液相色谱检测盐酸西布曲明的条件,提高了检测的抗干扰能力和检测限;探索了最佳质谱条件,提高了定性分析的可靠性.所采用的方法可用于准确检测保健食品中的盐酸西布曲明. 相似文献
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高效液相色谱表征高聚物* 总被引:1,自引:0,他引:1
最常用的测试高聚物的分子量和分子量分布的体积排除色谱(SEC)是高效液相色谱 (HPLC)的一个重要分支,HPLC的另一个重要分支是相互作用液相色谱, 它是20世纪90年代开始用于高分子分离和表征的研究领域。相互作用液相色谱可以根据高分子的化学结构(如共混物组成、共聚物组成、端基)来分离,它比SEC 有更高的分离效率。本文介绍了高聚物液相色谱的分离模式,并就高聚物体积排除色谱、相互作用液相色谱、临界液相色谱和全二维液相色谱用于分离和表征高聚物的研究进展进行了较系统的综述,并对该技术目前存在的问题和今后可能的发展前景进行了探讨。 相似文献
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综述了近十五年来液相色谱分析方法在环境水中农药残留分析中的应用,对各种常用的在线和离线样品预浓缩技术、检测器以及液相色谱与质谱等仪器的联用进行了讨论,并对液相色谱在农药残留分析中的应用前景进行了评价。 相似文献
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中药物质基础的高效液相色谱分离分析方法研究 总被引:2,自引:0,他引:2
高效液相色谱方法已成为中药物质基础研究的重要手段.在中药质量控制、中药标准品制备、活性化合物发现等方面发挥着不可替代的作用.然而我们的实验数据表明,一个中药材可能包含上万个化合物.中药物质基础的复杂性对高效液相色谱方法提出了巨大挑战.本文针对液相色谱方法在中药物质基础分离分析中存在的问题与难点,结合红花、黄连、姜黄三味药材样品,从亲水色谱分离模式、新型色谱固定相、二维液相色谱分离系统和液相色谱质谱联用技术等方面讨论了液相色谱的分离分析方法和发展方向.结果表明,高效液相色谱新技术新方法在中药复杂体系的分离分析中具有很大的发展潜力和应用前景. 相似文献
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It was shown that nonionic surfactants (NS) can be determined by potentiometry using liquid NS-selective electrodes. The effect of medium acidity and foreign substances on the operation of liquid NS-selective electrodes was studied. Some properties of NS-selective electrodes were determined. 相似文献
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A method for purity control of newly synthesized lactic acid–based liquid crystals has been developed. The electrokinetic chromatography proved to be suitable for the separation of these electroneutral substances from their impurities. The separations were performed in an acidic acetonitrile-based background electrolyte (BGE) with a pseudostationary phase formed by a cationic surfactant. During the optimization step, appropriate concentrations of cetyltrimethylammonium bromide, acetic acid, and water were seeked. In the optimized method, separations were carried out in acetonitrile with 1-mol/L acetic acid, 80-mmol/L cetyltrimethylammonium bromide, and 6% (v/v) water. Interesting positive effects of a small water content in the BGE on electroosmotic flow and resolution of liquid crystal substances from their impurities were observed and discussed. Samples of five liquid crystal substances, both pure and containing impurities from synthesis, were analyzed. The identification of analytes was based on a comparison of relative migration times related to the migration time of mesityl oxide. For all five samples, impurities were separated from the liquid crystals and the method thus showed its viability. To the best of our knowledge, this method is used for the first time for the purity control of newly synthesized liquid crystals. This method can be used to confirm or complement the results obtained by commonly used high-performance liquid chromatography and supercritical fluid chromatography methods. Furthermore, the electrokinetic chromatography method requires very small amounts of sample, solvents, and buffer constituents. Overall, its operational costs are significantly lower. 相似文献
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高效液相色谱-质谱联用分析无患子中的表面活性物质 总被引:2,自引:0,他引:2
应用高效液相色谱和大气压电离质谱联用技术 ,分离分析了无患子果皮中的表面活性成分。根据质谱结果确定其相对分子质量 ,根据源内的碰撞诱导解离 (CID)技术产生的碎片初步推测表面活性物质的结构 ,发现了数个未见文献报道的组分。 相似文献
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芦丁在离子液体双水相中分配性能 总被引:2,自引:1,他引:1
建立了室温离子液体四氟硼酸1-丁基-3-甲基咪唑([Bmim]BF4)和NaH2PO4组成的双水相萃取体系并用于对芦丁的萃取分离研究。考察了离子液体用量、芦丁的浓度、盐的加入量、溶液酸度和加入其它物质对芦丁在两相中分配的影响。结果表明,离子液在1.0~2.5 mL,磷酸二氢钠加入量在1.0~2.0 g,加入卢丁溶液0.5~2.5 mL,酸度在pH值为2~7范围,卢丁在离子液体双水相体系中有较高的萃取率(E%>90)。除阳离子表面活性剂外,其余大部分物质不影响相比和卢丁的测定。离子液相中卢丁的最大吸收波长为358 nm,与乙醇水溶液中比较,最大吸收波长发生紫移,表明离子液与卢丁发生了作用。利用离子液体双水相体系,测定了银杏叶中卢丁的含量。 相似文献
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The structural-dynamic features of ionic liquid-nonpolar substance systems are studied by means of molecular dynamics using Frenkel’s fundamental theory of a liquid and the phonon theory of the thermodynamics of a liquid, in combination with the DL_POLY_4.05 software package. Argon, methane, and benzene molecules serve as the dissolved substances. Model concepts are proposed and analyzed to describe the diffusion of molecules of a dissolved substance in an ionic liquid. It is shown that an increase in the mass of the molecules of a dissolved nonpolar substance correlates with their mobility in a hydrophilic ionic liquid (IL). This determines the diffusion of the components of dmim+/Cl? IL solutions and is responsible for the anomalous behavior of the solubility of nonpolar substances in them. 相似文献
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Michael Schulte Dieter Lubda Axel Delp Jules Dingenen 《Journal of separation science》2000,23(1):100-105
The use of monolithic silica sorbents for the isolation of substances by preparative liquid chromatography is demonstrated. Preparative liquid chromatography is recognized as a valuable technique for the isolation and purification of substances in the pharmaceutical and fine chemicals industry. The system technology has meanwhile reached a high standard, and the greatest future improvements are expected to arise from new and improved adsorbents. Monolithic silica sorbents offer some unique features for preparative liquid chromatography. They exhibit high efficiencies even at high flow rates due to their fast convective mass transfer and can therefore be used at very high mobile phase velocities, leading to high productivity and hence to maximum process economy. The benefits of this new type of adsorbent are illustrated for an example in batch‐chromatographic mode and an example using the continuous simulated moving bed (SMB) technology. 相似文献
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采用反相离子对高效液相色谱/蒸发光散射检测法研究了唑来膦酸及其有关物质的色谱分析与分离方法。优化了色谱条件,固定相为Hypersil C8柱,以含10 mmol/L正戊胺的5mmol/L乙酸铵缓冲液(用乙酸调节pH至7.0)-甲醇(体积比为97:3)为流动相,流速为1.0mL/min,蒸发光散射检测器检测。在该色谱条件下,唑来膦酸与其有关化合物(包括合成过程中残余的原料咪唑乙酸及分解产物亚磷酸、磷酸盐)的分离良好,唑来膦酸色谱峰与最近杂质峰的分离度大于1.5。本法简便快速,为唑来膦酸的常规分析提供了有效可靠的方法。 相似文献
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The sodium/liquid ammonia cleavage of the dimethoxybenzenes and related substances, reported in large part by Birch in 1947, has been re-examined with use of improved techniques. Remarkable patterns of reactivity (e.g., ortho > meta > para) that he described are confirmed and extended. They are agreeably rationalized by means of a simple, approximate adaptation from MO theory. 相似文献