Basic Principles of Chromatography

Georges Guiochon, Department of Chemistry, University of Tennessee, Knoxville, TN, 37996-1600, United States. Division of Chemical and Analytical Scicnce.s, Oak Ridge National Laboratory, Oak Ridge. TN, 37831-6120, United States 

Sources of Band A.symmetry and Tailing in Linear Chromatography 181 

Chromatography is the most powerful separation technique available. For reasons that will be made clear later, it is easy to implement chromatographic techniques with small samples, and to carry out separations on an analytical scale. Separated components are usually detected online, and sometimes they are also characterized, after which they are generally discarded. In preparative applications, the purified components are collected for further investigation, although new difficulties may be encountered in an attempt to 

The mobile phase is a fluid. The main criteria for its selection are  

It is not possible to review here the entire hi.story of chromatography and do justice to all the scientists who have contributed to designing and developing the dozens of major separation techniques based on the principle of chromatog- 

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The basic principle of chromatography separations can be described by thermodynamics using the distribution coefficient K (12) ... 

The purpose of this article was to provide the reader with a basic understanding of capillary electrophoresis and to describe how a technique such as MEKC uses basic principles of chromatography to perform separations which are not possible electrophoretically. As the applications for electrokinetic chromatography rapidly expand, the future direction will develop on two fronts ... 

Guiochon, G. Basic Principles of Chromatography in Ullmann s Encyclopedia of Industrial Chemistry, Vol. B5, VCH Verlagsgesellschaft, 1994. 

The book edited by Harrison and Rapso-manikis (1989) on environmental analysis using chromatography interfaced with atomic spectroscopy has chapters on basic principles of chromatography and AAS, interfaces between liquid chromatography and AAS and determination of individual elements. The book by Kebbekus and Mitra (1998) contains a chapter devoted to chromatographic methods, a discussion of which is also included in chapters on methods for air, water and solid sample analyses. 

Direct analysis of lipid classes enables faster and more efficient usage of analytical resources and sample material. Many of the direct analysis techniques are derived from the basic principles of chromatography described above. However, they have evolved specific instrumentation to enable (in most cases) improved separation... 

In forensic science, chromatography is used in the analysis of drugs of abuse, toxicology, fire debris analysis, environmental analysis, and explosives analysis, to name but a few. To understand each of the chromatographic techniques, especially HPLC as the topic of this primer, it is necessary first to explain what chromatography is and the basic principles of chromatography. 

From an engineer s point of view it is highly desirable to describe the chromatographic system by reduced parameters. This helps to understand some very basic principles of chromatography and to compare very different systems. Reduced parameters are dimensionless. Instead of the plate height H and mobile phase linear velocity u, one defines the reduced plate height h and the reduced velocity v by the following two equations ... 

Gas chromatography was developed in the early 1950s [8], Tens of thousands of publications and more than 250 textbooks on theory and practice have been published. The purpose of this article is not to write a new textbook on GC but rather to help newcomers in the field to find their way in the present state of the art of modern GC. For the basic aspects of GC, see - Basic Principles of Chromatography. Fundamental equations are given or repeated only to clarify some important statements. The terms, symbols, and nomenclature used are those that have been advi.sed by lUPAC 9],... 

Deflnition and Theoretical Background (- Basic Principles of Chromatography)... 

The following constitutes a general guide to the use of thin layer chromatography (TLC). Pertinent reference sources on the subject include [1]-13]. The discussion here is focused on precoated plates, since these have largely supplanted homemade layers. For further information on the relationship between TLC and other types of chromatography - Basic Principles of Chromatography. 

Errors introduced during movement of the solute through the sorbent layer include lateral diffusion during development, and problems can also arise from structural variations for different plates or variations between tanks. Lateral diffusion is a function of the relative rates of diffu.sion of solute and mobile phase (- Basic Principles of Chromatography). Errors due to lateral diffusion when substantially different amounts of solute are applied next to each other can be prevented by scoring the plate into strips ca. I cm wide prior to spotting. In this way two dissimilar samples can safely be developed side by side. Variation in... 

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