Terminology, chromatography

Schulte, M, and Epping, A. (2005) Fundamentals and general terminology, in Preparative Chromatography. 1st edn (ed. H. Schmidt-Traub), Wiley-VCH Verlag GmbH, Weinheim, pp. 9-49. 

Separations that take place in a chromatographic column are very similar to other types of separation, and it is for this reason that we will cover several of the more important separation techniques. A chromatographic column may be likened to a distillation column in many respects in fact, some of the terminology in chromatography is taken from distillation theory. 

With regard to terminology, we will use FI to mean flow injection as described above with an injection valve for sample introduction. Similarly, we will use SI as described above to mean sequential injection in which solutions are pulled into a holding coil via a multiposition valve, and pushed out through this valve to the separation system. The combination of a SI fluid-handling system with a separation column can be called SI chromatography. Some papers apply FI and SI terms more loosely to flow-based systems that may or may not follow these formal fluid-handling approaches as just defined. 

In planar chromatography, the fractions are not always transferred to another separation system, but rather a secondary separation is developed, orthogonally on the same chromatographic plate. Therefore, for all substances not completely separated it is possible that baseline separation can be achieved by means of a second separation process with an appropriate mobile (stationary) phase. Figure 8.2 shows that in the second dimension a theoretically unlimited number of secondary columns can be applied. Because of this, the terminology two-dimensional PC is not sufficiently... 

Capillary electrophoresis is similar to chromatography in many respects, and most of the words used in chromatography are also found in CE. For example, resolution and efficiency are common to both techniques and are defined in a similar way. However, some of the terminology is different, as illustrated in Table 4.1. For example, in chromatography, a column in used to separate the analytes in electrophoresis, a capillary is used. In chromatography a pump is used to propel the sample through the column in electrophoresis, there is no external pumping system, and the... 

Most chemometricians prefer inverse methods, but most traditional analytical chemistry texts introduce the classical approach to calibration. It is important to recognise that there are substantial differences in terminology in the literature, the most common problem being the distinction between V and y variables. In many areas of analytical chemistry, concentration is denoted by V, the response (such as a spectroscopic peak height) by y However, most workers in the area of multivariate calibration have first been introduced to regression methods via spectroscopy or chromatography whereby the experimental data matrix is denoted as 6X , and the concentrations or predicted variables by y In this paper we indicate the experimentally observed responses by V such as spectroscopic absorbances of chromatographic peak areas, but do not use 6y in order to avoid confusion. 

A general introduction is given in section 5.1. The specific problems of selectivity optimization in chromatography are explained in this section and the terminology that will be used throughout the rest of the chapter is introduced. 

The scope of chromatography and the relationship among techniques can be stated most clearly by categorizing the major variations and exploring their function and limits. While not all variations are in widespread use, some breadth is useful for perspective and for suggesting solutions to future problems. By and large we follow IUPAC terminology [2] more recent compilations of terms have been published [3,4]. 

The names used for adsorption and partition chromatography in GC are gas-solid chromatography (GSC) and gas-liquid chromatography (GLC), respectively. With liquid as the mobile phase (LC), the equivalent terminology is liquid-solid and liquid-liquid chromatography, or LSC and LLC respectively. 

Stahl, E., Suggestions for the standardization of procedures and terminology of thin-layer chromatography. Introductory paper. J. Chromatogr. 33, 273-279 (1968). 

The same principles are involved in two different types of operation saturation, in which one or more solute components are separated from the solvent, and chromatography, in which two or more solute components are separated from one another. Saturation operations will be discussed in this section, and chromatography in the next. The terminology will be that adopted in previous papers by Vermeulen, Hiester, and co-workers (Hl-6, V3-6). 

A glossary of chromatographic terms and a table of chromatographic symbols are included in the appendices at the end of this book. Further information on the terminology of chromatography is available in the literature [8]. 

The general principles of chromatography have been discussed in Chapter 2. However, a more detailed account in the context of GC is presented herein the reader is also referred to the Glossary for additional detail and explanations of the terminology used. The treatment of theoretical aspects is at a level which should enable the analyst to obtain maximum efficiency and performance from the system and application. 

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