Multidimensional thin-layer chromatography

We have purposely narrowed the scope of all multidimensional chromatography to those techniques that incorporate separations in the liquid phase and to those in which the use of the comprehensive mode prevails but is not exclusive. This text neither incorporates elements of multidimensional thin-layer chromatography, multidimensional separations in gel media such as those commonly employed for the separation of complex mixtures of proteins, nor the techniques that utilize multidimensional gas chromatography. Some of the same principles apply, particularly in the theory section, but our emphasis is strictly on separations carried out in the liquid phase and by columns, rather than in the gas phase or in planar configurations. 

The theoretical work that exploited the advantages of the multidimensional separation format appears to have been developed much later than the original experimental work. One of the earliest studies was conducted by Connors (1974), who assumed that the distribution of spots on a two-dimensional thin-layer chromatography (2DTLC) plate could be modeled using a Poisson distribution of data on each retention axis. He then constructed equations that related the number of chromatographic systems needed to resolve a specific number of compounds. One... 

This effect is illustrated in Fig. 17.1. Multidimensional chromatography separations can be done in planar systems or coupled-column systems. Examples of planar systems include two-dimensional thin-layer chromatography (TLC) (Consden et al., 1944 Grinberg et al., 1990), where successive one-dimensional TLC experiments are performed at 90° angles with different solvents, and 2D electrophoresis, where gel electrophoresis is run in the first dimension followed by isoelectric focusing in the second dimension (O Farrell, 1975 Anderson et al., 1981 Celis and... 

IRMS LC MDGC MS MSA NIF NMR OAV OSV PCA RAS RP SDE SFE SIM SNIF SPME TIC TLC Stable Isotope Ratio Mass Spectrometry Liquid Chromatography MultiDimensional Gas Chromatography Mass Spectrometry Multivariate Sensory Analysis Nasal Impact Frequency Nuclear Magnetic Resonance spectroscopy Odor Activity value Odor Spectrum Value Principal Component Analysis Retronasal Stimulation Reversed Phase Simultaneous steam Distillation Extraction Supercritical Fluid Extraction Selected Ion Monitoring Surface of Nasal Impact Frequency Solid Phase Micro Extraction Total Ion Current Thin Layer Chromatography... 

See also Chromatography Overview Multidimensional Techniques. Gas Chromatography Detectors Mass Spectrometry. Liquid Chromatography Liquid Chromatography-Mass Spectrometry. Thin-Layer Chromatography Overview Principles. 

Srivastava, M.M. 2011. An overview of HPTLC A modern analytical technique with excellent potential for automation, optimization, hyphenation, and multidimensional applications. In Srivastava, M. (Ed.), High Performance Thin Layer Chromatography (HPTLC), Springer, Heidelberg, Germany, pp. 3—26, Chapter 1. 

In the area of high-resolution s-NMR new developments and applications are mainly taking place in the field of multidimensional NMR spectroscopy (e.g. domain studies in polymers and polymer blends). Thin-layer chromatography combined with HRMAS s-NMR can be used for compound identification without the need for substance elution from the stationary phase [662]. 

Practically all types of commercially available thin-layer plates and precoated sheets can be used silica gel, cellulose, kieselguhr, alumina and glass fibres. It is, perhaps, not necessary to emphasize that both one- and two-dimensional arrangements can be materialized as well as different combinations with chromatography and multidimensional procedures [65]. 

LC-TLC coupling constitutes one possibility for carrying out multidimensional LC. Thus HPLC (usually reversed-phase chromatography) is coupled with thin layer (adsorption) chromatography in such a way that the eluate from the HPLC column is transferred via a capillary column to a mechanically transported TLC plate [289], [290]. 

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