Chromatographic and electrophoretic procedures for analyzing plant pigments of pharmacologically interests

The achievements in the use of chromatographic and electrophoretic techniques including thin-layer chromatography, high-performance liquid chromatography and capillary electrophoresis for the separation and quantitative determination of pharmacologically interesting plant pigments in various sample matrices such as medicine, plant, foods and food products, etc. are surveyed and critically evaluated.     

Review of thin-layer chromatography in pesticide analysis: 2014–2016

ABSTRACT

Publications reporting techniques and applications of thin-layer chromatography (planar chromatography) for the separation, detection, qualitative and quantitative determination, and preparative isolation of pesticides and their metabolites are reviewed for the period from November 1, 2014 to November 1, 2016. Analyses are described for a variety of sample types and pesticide classes. In addition to references on residue analysis, studies such as pesticide chromatographic retention, identification and characterization of natural pesticides, metabolism, bioactivity, degradation, soil mobility, and lipophilicity are covered. The unique advantages of thin-layer chromatography in presenting results as a stored image on an open stationary phase are addressed.     

Application of different modes of thin-layer chromatography and mass spectrometry for the separation and detection of large and small biomolecules

Biomolecules are widespread throughout the world. A biomolecule is any organic molecule produced by a living organism, including large polymeric molecules such as proteins, polysaccharides and nucleic acids. Many sample preparation techniques are used in biomolecule analysis; the method selected depends on the complexity of the sample, the nature of the matrix and the analytes, and the analytical technique available. This review covers the current state of knowledge on thin-layer chromatography and mass spectrometry for qualitative analysis of biomolecules. In the first part of the paper the reader will gain useful information to avoid some problems about performing various modes of thin-layer chromatography combined with mass spectrometry experiments and in the second part he will find useful information for application of these techniques for separation, detection, and qualitative investigation of structures and quantitative determination of biomolecules such as proteins, peptides, oligonucleotides, amino acids, DNA, RNA, and lipids.     

Binding of low molecular mass compounds to proteins studied by liquid chromatographic techniques

The newest achievements in the application of miscellaneous liquid chromatographic techniques such as size-exclusion, ion-exchange and reversed-phase high-performance liquid chromatography, and thin-layer chromatography for the elucidation of the various aspects of the binding of ligands to proteins are compiled and briefly discussed. Examples of employment in pharmaceutical and clinical chemistry, drug design, enzyme kinetic studies and environmental protection are presented.     

Design of experiment techniques for the optimization of chromatographic analysis conditions: A review

Design of experiment (DoE) techniques have been widely used in the field of chromatographic parameters optimization as a valuable tool. A systematic literature review of the available DoE techniques applied to the development of a chromatographic analysis method is presented in this paper. First, the most common available designs and the implementation steps of DoE are comprehensively introduced. Then the studies in recent 10 years for the application of DoE techniques in various chromatographic techniques are discussed, such as capillary electrophoresis, liquid chromatography, gas chromatography, thin-layer chromatography, and high-speed countercurrent chromatography. Current problems and future outlooks are finally given to provide a certain inspiration of research in the application of DoE techniques to the different chromatographic techniques field. This review contributes to a better understanding of the DoE techniques for the efficient optimization of chromatographic analysis conditions, especially for the analysis of complex systems, such as multicomponent drugs and natural products.     

Recent advances of online coupling of sample preparation techniques with ultra high performance liquid chromatography and supercritical fluid chromatography

Ultra high performance liquid chromatography and supercritical fluid chromatography techniques are favored because of their high efficiency and fast analysis speed. Although many sample preparation techniques have been coupled with common liquid chromatography online, the online coupling of sample preparation with the two popular chromatography techniques have gained increasing attention owing to the increasing requirements of efficiency and sensitivity. In this review, we have discussed and summarized the recent advances of the online coupling of sample preparation with ultra high performance liquid chromatography and supercritical fluid chromatography techniques. The main sample preparation techniques that have been coupled with ultra high performance liquid chromatography online are solid‐phase extraction and in‐tube solid‐phase microextraction, while solid‐phase extraction and supercritical fluid extraction are the main techniques that have been coupled with supercritical fluid chromatography online. Especially, the strategies for online coupling of sample preparation with chromatography techniques were summarized. Typical applications and growing trends of the online coupling techniques were also discussed in detail. With the increasing demands of improving the efficiency, throughput, and analytical capability toward complex samples of the analysis methods, online coupling of sample preparation with chromatography techniques will acquire further development.     

Thin-layer chromatography/electrospray ionization triple-quadrupole linear ion trap mass spectrometry system: analysis of rhodamine dyes separated on reversed-phase C8 plates

The direct analysis of separated rhodamine dyes on reversed-phase C(8) thin-layer chromatography plates using a surface sampling/electrospray emitter probe coupled with a triple-quadrupole linear ion trap mass spectrometer is presented. This report represents continuing work to advance the performance metrics and utility of this basic surface sampling electrospray mass spectrometry system for the analysis of thin-layer chromatography plates. Experimental results examining the role of sampling probe spray end configuration on liquid aspiration rate and gas-phase ion signal generated are discussed. The detection figures-of-merit afforded by full-scan, automated product ion and selected reaction monitoring modes of operation were examined. The effect of different eluting solvents on mass spectrum signal levels with the reversed-phase C(8) plate was investigated. The combined effect of eluting solvent flow-rate and development lane surface scan rate on preservation of chromatographic resolution was also studied. Analysis of chromatographically separated red pen ink extracts from eight different pens using selected reaction monitoring demonstrated the potential of this surface sampling electrospray mass spectrometry system for targeted compound analysis with real samples.     

染料中间体二氰基─4─硝基苯胺的分析

应用薄层色谱（ＴＬＣ）和紫外光谱法（ＵＶ）对二氰基－４－硝基苯胺合成中涉及的主要产物进行分析，比传统化学法快速，简单，准确，回收率９９．１％～１０１．１％，相对标准偏差０．４８％～０．８５，在０～６ｍｇ／Ｌ范围内遵守比耳定律。     

染料中间体二氰基─4─硝基苯胺的分析

应用薄层色谱（ＴＬＣ）和紫外光谱法（ＵＶ）对二氰基－４－硝基苯胺合成中涉及的主要产物进行分析。比传统化学法快速、简单、准确，回收率９９．１％～１０１．１％，相对标准偏差０．４８％～０．８５％，在０～６ｍｇ／Ｌ范围内遵守比耳定律。     

Direct ionization methods in mass spectrometry: An overview

Within this paper a sub-group of ambient ionization mass spectrometry namely direct ionization mass spectrometry techniques are reviewed. They are characterized by the generation of an electrospray directly from the sample investigated. Prominent representatives include paper spray mass spectrometry, tissue spray mass spectrometry, probe electrospray ionization or thin-layer chromatography mass spectrometry. Applications of all major direct ionization techniques within different fields such as biomedical analysis, analysis of natural products, analysis of technical products and food analysis, just to name a few, are discussed and relevant parameters are listed in five Tables.     

Lipophilicity determination of some fully protected peptides and amino acids

Summary The lipophilicity of 21 fully protected peptides and amino acids was determined by reversed-phase thin-layer chromatography. The R_M values decreased linearly with growing methanol concentration of the eluent. The sequence and conformation of molecular substructures did not significantly influence the lipophilicity. The presence of salt and ammonia in the eluent had a negligible impact on retention; the effect of the pH value was also low. In the presence of 1M and 2M acetic acid the retention of each compound considerably decreased. Acetic acid also changed markedly the selectivity. Our data suggest that the acetic acid has a preponderant role in changing the retention and selectivity of fully protected peptides and amino acids in reversedphase thin-layer chromatography.     

Coupling HPLC to GC: why? How? With what instrumentation?

Coupling LC to GC alleviates sample preparation in the sense of preseparation, cleanup, or enrichment and replaces conventional methods such as column liquid chromatography, enrichment by or filtration through sample preparation tubes, preparative thin-layer chromatography, or liquid-liquid partitioning. LC is more efficient in separation power, more rapid, and allows fully automatic integration of sample preparation into GC. Advantages are discussed for selected applications. The transfer techniques, as well as some key requirements for an LC-GC instrument, are briefly summarized.     

Hyphenations in planar chromatography

This review is focused on planar chromatography and especially on its most important subcategory high-performance thin-layer chromatography (HPTLC). The image-giving format of the open, planar stationary phase and the post-chromatographic evaporation of the mobile phase ease the performance of various kinds of hyphenations and even super-hyphenations. Examples in the field of natural product search, food and lipid analysis are demonstrated, which point out the hyphenation with effect-directed analysis (EDA) and mass spectrometry and illustrate the efficiency gain. Depending on the task at hand, hyphenations can readily be selected as required to reach the relevant information about the sample, and at the same time, information is obtained for many samples in parallel. The flexibility and the unrivalled features through the planar format valuably assist separation scientists.     

Toxicological screening by liquid chromatography

Toxicological screening commonly requires analysis of biological specimens by a variety of colorimetric, immunological and chromatographic techniques. Gas chromatography and thin-layer chromatography are useful for simultaneous identification of multiple drug classes, but both methods require sample pretreatment. Recently, liquid chromatography has been applied to untreated urine and serum. A series of columns are utilized for sample purification, as well as efficient separation of drugs. Multiple wavelength UV detection provides sufficient data for qualitative identification of drugs and their metabolites.     

A review of advances in two-dimensional thin-layer chromatography

Although there are many simple thin-layer chromatography (TLC) separations, many more are complex and involve more than a few components, that means having to use special high-performance TLC (HPTLC) plates or microspotting or banding devices to increase its resolving power if developing in only one direction. However, adding a second development to perform two-dimensional TLC (2D TLC) allows even better resolution of complex samples. This is because different modes of chromatography are being invoked by the use of one stationary phase with two mobile phases, bilayer plates, graft TLC, or multidimensional TLC. This paper is a review of recent applications that have benefitted from using 2D TLC in its various forms. They were chosen for their variety of sample types as well as the unique choices of plates and/or mobile phases made by the researchers to yield improved separations.     

High performance stationary phases for planar chromatography

The kinetic performance of stabilized particle layers, particle membranes, and thin films for thin-layer chromatography is reviewed with a focus on how layer characteristics and experimental conditions affect the observed plate height. Forced flow and pressurized planar electrochromatography are identified as the best candidates to overcome the limited performance achieved by capillary flow for stabilized particle layers. For conventional and high performance plates band broadening is dominated by molecular diffusion at low mobile phase velocities typical of capillary flow systems and by mass transfer with a significant contribution from flow anisotropy at higher flow rates typical of forced flow systems. There are few possible changes to the structure of stabilized particle layers that would significantly improve their performance for capillary flow systems while for forced flow a number of avenues for further study are identified. New media for ultra thin-layer chromatography shows encouraging possibilities for miniaturized high performance systems but the realization of their true performance requires improvements in instrumentation for sample application and detection.     

快速色谱

基于柱液相色谱和薄层色谱之间的关系,讨论如何为快速色谱选择流动相,并介绍此技术手工操作的步骤.     

色谱专家系统的应用和发展

随着科学技术的发展,色谱专家系统作为一种人工智能方法亦在不断发展,并在实际工作中发挥着越来越重要的作用。该文综述了作者的研究小组在色谱专家系统研究方面的进展,重点介绍从研究气相色谱专家系统开始,到应用色谱专家系统的思想,运用气相色谱、液相色谱和毛细管电泳新技术解决石化、环境、疾病诊断、基因分析和药物分析等领域实际问题的工作。引用相关文献64篇。     

液相色谱法分离金属螯合物的进展

综述了用薄层液相色谱法和柱液相色谱法分离金属螯合物的进展及其在金属离子分析方面的应用。