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摘要利用改进的可视化装置, 研究了10°锥角的台锥型液相色谱柱内的谱带流型与柱参数变化的关系. 将有机玻璃柱管加工成内圆台外方型的一体结构, 选择折射率一致的色谱固定相硅胶和流动相环己烷, 使整个色谱柱成为高度清晰的透明体, 能直接观察柱中彩色样品谱带的动态三维流型. 研究结果表明, 在实验条件范围内, 流动相流速对谱带流型无影响, 填料的形状和性质对塞子状流型有一定程度的影响. 比较了柱长为5cm和等比例放大后柱长为10cm锥型柱内的流型, 发现放大后的锥型柱内仍然保持塞子状流型, 总柱效等比例增加. 表明继续按比例放大成为工业规模色谱柱后仍能保持塞子状流型. 相似文献
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茶叶指纹谱的毛细管胶束电动色谱法研究 总被引:6,自引:0,他引:6
用胶束电动色谱法建立了茶叶的色谱指纹谱并用于分析10种中国名茶。这种色谱指纹谱是由相对保留值(α)和相应的相对峰面积(Sr)组成的。该方法将色谱图转换成数据表,实现了图谱的数据化;并且以相对保留值表示各色谱峰的峰位,大大减少了各种操作条件对色谱相对保留值的影响,降低了色谱峰峰位变化的波动性,提高了样品间的可比性。这种色谱指纹谱在没有标准品的情况下也可得出可靠的、有意义的结果。优化后的色谱条件是:电泳电解质为硼砂0.02 mol/L 、十二烷基硫酸钠(SDS)浓度为0.025 mol/L 的溶液(pH 相似文献
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谱峰漂移校正技术结合平行因子分析方法被应用于中药色谱重叠峰信号分辨. 谱峰漂移校正技术的使用, 使得数据的三线性得以加强, 更适合于平行因子分析方法的分辨. 本文通过对中药延胡索色谱数据分辨, 并与经典多元曲线分辨方法对比来验证谱峰漂移校正技术结合平行因子分析方法的正确性. 相似文献
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〕本文在建立整个液相色谱系统质量平衡模型的基础上,求得了柱内的柱末端色谱谱带的虚拟一级矩和二级中心矩,进而利用计算机技术详细考察了色谱参数对柱末端色谱谱带半宽度的影响。结果表明不同k'的组分在k'>0.5左右时的色谱谱带半宽度基本一致;但当k'<0.5左右时,随着k'的下降,柱末端谱带半宽度也下降。如有适当的柱外效应存在,则能有效地改变这一现象。本文还详细讨论了使得色谱流出曲线的半宽度不同的作为色谱基本分离过程之一的柱末端过程,从而推测半峰宽规律可用于不同等度和梯度条件下的色谱峰半宽度的预测。 相似文献
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X射线衍射多谱峰匹配强度比定量相分析方法 总被引:4,自引:0,他引:4
提出了1种采用x射线衍射多谱峰匹配强度比进行定量相分析的新方法;该法是利用混合物样品x射线衍射谱图中的多谱峰数据,结合ICDD卡中的各相标准谱峰的相对强度分布数据进行最小二乘法回归分析,求得混合物样品中各相间的多谱峰匹配强度比;以多谱峰匹配强度比取代通常采用的特定单一谱线强度比,用于混合物样品的x射线衍射定量相分析,有利于提高定量相分析的精度;采用多谱峰匹配强度比结合绝热法和基体清洗法X射线衍射定量相分析原理,通过对4组分混合物样品的分析,证实实验结果和理论完全一致。 相似文献
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Wilbur L. Saxton 《Journal of separation science》1984,7(3):118-122
A terminal band length is defined here as the length of a dispersed solute band as it emerges from the chromatographic column. The number of terminal band lengths per column can be used in the same way that the number of theoretical plates per column is used to measure and compare chromatographic efficiencies, but with greater insight since the proposed unit of measure is an easily visualized, real entity. In addition, the height equivalent to a theoretical plate (HETP) can be regarded as a ratio of the terminal band lenght to sixteen times the number of equivalent terminal band lengths that could be contained in tandem in the column. This concept offers another approach to understanding the meaning of the term, HETP. The terminal band length of a series of homologues is constant and independent of retention time above a certain solute molecular size and column capacity ratio. Within those conditions the correlation between the recorded peak width and retention time during isothermal analysis occurs primarily as a result of change in solute velocity. 相似文献
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《Analytical letters》2012,45(10):2105-2128
ABSTRACT The embedded chromatographic peaks usually can not be completely resolved by conventional multivariate resolution methods. The resolution condition of a certain component in two-way data is first reviewed. A modified orthogonal projection resolution (OPR) algorithm and new entropy maximization (EM) method are then proposed to resolve embedded chromatographic peaks in this paper. The modified OPR algorithm performs more precisely than conventional orthogonal projection resolution algorithm in resolving the chromatography of minor peak. The entropy criterion defined on the differential chromatography could obtain an approximate solution in resolution of the major chromatographic peak. Simulated and real data show that the modified OPR and entropy maximization (EM) methods perform well in solving the embedded problem. 相似文献
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《Electrophoresis》2018,39(16):2144-2151
The chromatographic behavior of new biogenic purine nucleosides in hydrophilic interaction liquid chromatography was examined on three different stationary phases, namely bare silica, and amide‐ and cyclofructan‐based stationary phases. The effects of buffer concentration, pH and acetonitrile‐to‐aqueous‐part ratio in the mobile phase on retention and peak shape were assessed. The retention coefficients and peak symmetry values substantially differed with respect to analytes´ structures, stationary phase properties and mobile phase composition. The bare silica column was unsuitable for these compounds under the chromatographic conditions tested due to very broad and asymmetrical peaks. Furthermore, the cyclofructan‐based stationary phase provided almost Gaussian peak shapes of all deazapurine nucleosides under most conditions tested. Therefore, the cyclofructan‐based stationary phase is the most suitable choice for the chromatographic analysis of nucleosides. 相似文献
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《Analytical letters》2012,45(2):363-378
Abstract Reliable analysis with high performance liquid chromatography (HPLC) requires purity of the eluting peak. The present work has combined the advantages of the availability of full spectral data from HPLC photodiode array UV detector and computer algorithms to perform chromatographic peak purity check. A deconvolution technique based on multicomponent analysis has been applied to the UV spectra of co-eluting components. This method employs residual error (Relative-fit-error, RFE) between predicted spectrum and analyte's spectrum to detect presence of other component or contaminant. Typical RFE values for uncontaminated chromatographic peaks of norethisterone and ethynyloestradiol range between 1 and 3, while contaminated peaks have RFE values as large as 145. A systematic increase in ‘relative-fit error’ from 1.10 to 145 was observed for peaks of norethisterone when contaminated to varied extent with ethynyloestradiol. Extent of peak overlap in chromatogram was also mapped out with this technique. The co-prescribed oral contraceptive, norethisterone and ethynyloestradiol were used as model in this work. An advantage of the method is its applicability when the contaminant's spectrum is unavailable. The method, unlike several earlier techniques, is also applicable to chromatograms with concidental elution time for the components. 相似文献
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《Analytical letters》2012,45(14):2475-2492
Abstract Recently, the fingerprinting approach using chromatography has become one of the most potent tools for quality assessment of herbal medicine. Due to the complexity of the chromatographic fingerprint and the irreproducibility of chromatographic instruments and experimental conditions, several chemometric approaches such as variance analysis, peak alignment, correlation analysis, and pattern recognition were employed to deal with the chromatographic fingerprint in this work. To facilitate the data preprocessing, a software named Computer Aided Similarity Evaluation (CASE) was also developed. All programs of chemometric algorithms for CASE were coded in MATLAB5.3 based on Windows. Data loading, removing, cutting, smoothing, compressing, background and retention time shift correction, normalization, peak identification and matching, variation determination of common peaks/regions, similarity comparison, sample classification, and other data processes associated with the chromatographic fingerprint were investigated in this software. The case study of high pressure liquid chromatographic HPLC fingerprints of 50 Rhizoma chuanxiong samples from different sources demonstrated that the chemometric approaches investigated in this work were reliable and user friendly for data preprocessing of chromatographic fingerprints of herbal medicines for quality assessment. 相似文献
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Extracolumn band broadening in multidimensional systems utilizing flow switching is clearly undesirable. In certain cases, i.e. capillary recycle gas chromatography, the success of an experiment is contingent on the minimization of pre- and post-column dispersion of the peaks. Knowledge of these sources of peak distortion is necessary to optimize the experimental design. A system that extracts statistical parameters from real chromatographic peaks is discussed and used to evaluate band broadening in a capillary recycle experiment. 相似文献
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本从色谱峰的EMG模型出发,通过对重叠色谱峰的模拟和回归分析,提出了一种三元重叠色谱峰的面积的定量方法,三元重叠色谱峰的每一个峰面积可以由峰面积比和总面积求得,此法所需的数据都由实验色谱图上测得,峰面积计算结果的相对误差小于±5%,适用于相对峰谷为50%-95%的三元重叠色谱峰面积的定量。 相似文献
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Lee WC Cheng CH Pan HH Chung TH Hwang CC 《Analytical and bioanalytical chemistry》2008,390(4):1101-1109
Recent efforts in the investigation of chromatographic characterization of molecularly imprinted polymers (MIPs) have focused
mainly on the nature of heterogeneous binding sites. More data on the thermodynamics than on the kinetic features of MIP columns
have been published. The present article addresses the sources of peak broadening and tailing, which are the main drawbacks
often associated with imprinted polymers in chromatography for practical applications. With use of the theory of nonlinear
chromatography, the peak properties of a MIP column, including the retention and peak broadening and tailing, can be well
interpreted. Efforts to improve chromatographic efficiency using MIPs prepared by approaches different from the conventional
method, including covalent imprinting and the format of uniformly sized spherical microbeads, are reviewed and discussed.
This review leads to the conclusion that nonlinear chromatography theory is useful for characterizing chromatographic features
of MIP columns, since a MIP is essentially an affinity-based chromatographic stationary phase. We expect more theoretical
and experimental studies on the kinetic aspects of MIP columns, especially the factors influencing the apparent rate constant,
as well as the analysis of the influences of mobile-phase composition on the chromatographic performance. In addition to revealing
the affinity interaction by molecular recognition, slow nonspecific interactions which may be inherited from the imperfect
imprinting and may be involved in the rebinding of the template to MIPs also need to be characterized.
Figure The peak broadening and tailing associated often with molecularly imprinted polymers (MIPs) in column chromatography for practical
applications can be well characterized by the theory of nonlinear chromatography. 相似文献
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《Analytical letters》2012,45(2):373-390
ABSTRACT A genetic algorithm for resolution of overlapping chromatographic peaks (GAROCP) using real-number coding, non-uniform mutation and arithmetical crossover methods is described in this paper. It was applied to resolution of highly overlapped multicomponent high-performance liquid chromatographic peaks by fitting experimental chromatogram to the exponentially modified Gaussian (EMG) model. The genetic algorithm was used to find the minimum of fitting error to optimize the parameters in the EMG functions which determine the shape and area of each peak. The applicability of the method was investigated with both simulated signals calculated by EMG functions and experimental multicomponent overlapping chromatograms. 相似文献