共查询到20条相似文献,搜索用时 609 毫秒
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牙本质中天冬氨酸消旋化程度的测定——手性毛细管气相色谱法与高效液相色谱法的比较 总被引:1,自引:0,他引:1
应用手性毛细管气相色谱法(酸性异丙醇、三氟乙酸酐为衍生试剂)、高效液相色谱法(邻苯二甲醛-N-乙酰-L-半胱氨酸为手性衍生试剂)同时测定人类第一磨牙牙本质中天冬氨酸的消旋化程度,结果表明,两者均可有效地用于天冬氨酸对映体的分离测定,但气相色谱检测限(0.2pmol)低于高效液相色谱(1.0pmol),而变异系数(7%)、总分析时间(100min)均高于高效液相色谱(分别对应为4%,31min)。 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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E M Bargar 《Journal of chromatography. A》1987,417(1):143-150
An automated high-performance liquid chromatographic (HPLC) column-switching system is described for the analysis of medroxalol, a potential antihypertensive agent, in plasma. The HPLC system uses two six-port switching valves with a Corasil C18 short pre-column for an on-line sample clean-up and an SGE ODS analytical column for separation. Plasma samples were diluted with a phosphate buffer (pH 7.2) containing an internal standard and aliquots were injected directly on the HPLC system. The column-switching system was applicable to continuous analysis of hundreds of plasma samples since this technique provided very efficient on-line sample clean-up and regenerated the pre-column effectively. Results were in good agreement and the total analysis time was one third that of an alternative method. 相似文献
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High-performance thin-layer chromatographic (HPTLC) analysis of non UV-active phospholipids in biological matrixes is a common method for separation, detection, and quantitation. Liposomes containing new alkylphosphocholines and analogues with enhanced cytostatic activity had been prepared. The liposomal formulations were designed to enable the intravenous application of the alkylphosphocholines and analogues and to reduce dose-limiting toxicities observed after oral administration. For quality control the liposomes were analyzed by HPTLC for content of 1,2-dipalmitoyl-sn-glycero-3-phosphoglycerol (DPPG), cholesterol, alkylphosphocholines, and analogues and their related compounds (main degradation products). Due to the differences in lipophily of the compounds, different mobile phases were necessary to achieve separation. Automated Multiple Development was used to reduce the number of plates and to improve the selectivity and the capacity of the chromatographic system to separate the described alkylphosphocholines and analogues from DPPG and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine in one chromatographic system. 相似文献
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A rapid and sensitive high-performance liquid chromatographic method for the analysis of beta- and gamma-cyclodextrin in aqueous biological fluids such as plasma, urine, or tissue homogenate is described. The chromatographic system consists of a microBondapak Phenyl column as stationary phase and a mobile phase of water with 10% methanol. After post-column addition of an alkaline solution of phenolphthalein, negative colorimetric detection is used. The elution solvent and post-column reagent were mixed in a capillary tubing of 1.5 m (1.0 mm I.D.). Two methods of sample treatment are given, one for large (1.0 ml) and one for small (0.1 ml) sample volumes. Both methods were shown to be linear and reproducible. The detection limit for beta-cyclodextrin was 1.0 microgram/ml (0.77 nmol/ml). The method was used in the determination of some pharmacokinetic parameters of beta-cyclodextrin in rats after intravenous injection. 相似文献
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6-Keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) in human urine is considered to be a reflection of renal prostacyclin production. Because of the large amounts of unidentified eicosanoid metabolites in urine that may potentially bind to 6-keto-PGF1 alpha antisera, most radioimmunoassays include chromatographic purification of urine. A comparison of chromatographic techniques and of antisera to 6-keto-PGF1 alpha for the assay of human urine is described. Gas chromatography--negative-ion chemical-ionization mass spectrometry (GC--NICI-MS) was used as the reference method. Radioimmunoassays were performed with each of four antisera combined with each of three chromatographic purification systems (silicic acid, Sephadex LH-20, reversed-phase high-performance liquid chromatography). There was marked variability in the results; however, there was at least one chromatographic method for each antiserum that yielded results comparable to GC--NICI-MS. Direct radioimmunoassay of urine without chromatography yielded markedly elevated and variable results for the four antisera. In contrast, the four antisera gave very similar results with direct assay of media from isolated perfused organs. Thus, for the radioimmunoassay of 6-keto-PGF1 alpha in human urine, each antiserum is sensitive to different contaminants in urine and must be individually matched to a chromatographic purification system. 相似文献
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A method is described that enables soluble and insoluble samples to be applied to ferromagnetic wires. The principle of the method consists in pressing the sample on to a flattened Curie-point wire at a pressure of 15 tonnes. It is shown that this method is suitable for a wide variety of polymers and for inorganic materials. As the pyrolysis—gas chromatographic results obtained are not only influenced by the pyrolysis itself but also to a large extent by the gas chromatographic process, a number of considerations are given with respect to the use of capillary gas chromatography in combination with a Curie-point pyrolyser. The sample application technique described has also been used to check the inertness of the chromatographic system by the preparation of Curie wires loaded with Tenax. These wires have been used for the “injection” of volatile compounds, such as a Grob mixture, with the pyrolyser system. 相似文献
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A simple analytic approach is described for the accurate determination of the concentration of components which give rise to partially overlapped chromatographic peaks. This method requires neither deconvolution processes nor chromatographic separation of the peaks. From the empirical point of view a bi-quadratic function has been found relating the area of an unresolved peak with the concentrations of the related analyte and of the interfering one. Such concentrations are then computed by solving the related non linear system of equations by the Newton-Raphson method. 相似文献
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Normal-phase high-performance liquid chromatographic separation of non-derivatized ganglioside mixtures 总被引:4,自引:0,他引:4
A new analytical and semi-preparative high-performance liquid chromatographic method for the separation of a brain ganglioside mixture into individual components is described. Gangliosides were applied to a LiChrosorb-NH2 column and eluted with the solvent system acetonitrile-phosphate buffer at different volume ratios and ionic strengths. The elution profile was monitored by flow-through detection of UV absorbance at 215 nm. The separation of mono- to polysialogangliosides was performed in one step in a total elution time lower than 90 min and with high reproducibility. 相似文献
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A simple liquid chromatographic method combined with tandem mass spectrometry (LC-MS-MS) is described for the analysis of aminoglycoside antibiotics. Clinically these antibiotics may cause both ototoxicity and nephrotoxicity; therefore, the monitoring of aminoglycoside levels in patient plasma is required for protecting human health. In this study separation of the method is based on ion-pair chromatographic technology on a short capillary reversed-phase C18 column. The method was successfully applied to analyze amikacin in human plasma. In human plasma after deproteinisation with HFBA, an aliquot of 1 microL supernatant was injected into the chromatographic system. Only a small amount of plasma sample, 10 microL, is sufficient for the monitoring of amikacin levels in clinically therapeutic range. The relative standard deviations (RSD) of the method for intra- and inter-day analyses (n=5) are less than 5.8%. Application of this method for the trace analysis of amikacin in human plasma proved simple and workable. 相似文献
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E. G. Sumina S. N. Shtykov V. G. Berezkin D. A. Zagniboroda V. Z. Atayan 《Journal of Analytical Chemistry》2009,64(12):1226-1234
A new version of thin-layer chromatography with controlled vapor phase is described. It has no analogues in planar and liquid
chromatography. The method is based on a dynamic change in the physicochemical properties of a chromatographic system as a
result of the contact of the plate bearing analytes with a vapor phase of certain composition created in the chromatographic
chamber. The active vapor phase is created either by pumping a gas through the chromatographic chamber or by introducing a
solvent vapor from another part of the chamber. The composition and properties of the mobile phase are controlled immediately
in the course of separation by means of absorption or adsorption of one or another gas with the mobile or stationary phase.
By the examples of benzoic acids and nitroaniline isomers in the presence of carbon oxide and vapors of acetic acid, ammonia,
and ethanol, it was shown that this procedure utilizes the difference in the protolytic and solvation properties of adsorbates
for changing the adsorption equilibrium and the selectivity and efficiency of separation. 相似文献
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A thin-layer chromatographic system is described for the separation of diphenhydramine and bromodiphenhydramine which is based on a reverse phase paper chromatographic system developed by J. Vecerková (2,3) in 1962. Chromatographic systems for this separation described in the literature and several systems attempted in this laboratory using normal chromatography have not proven successful. The method using reverse phase thin-layer chromatography involves a stationary phase of mineral oil on silica gel G and a mobile phase of ethanol:water:ammonium hydroxide, 28% NH3, (55:43:2). A 10-cm length of run requires about three hours and provides an excellent separation of the two compounds for identification-differentiation purposes. 相似文献