Chromatography basic principles

Ion Exchange Chromatography - Basic principles of ion exchange chromatography and studies conducted from Texas A M University. http //ntri.tamuk.edu/fplc/ion.html. 

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. 

Chromatography Basic Principles, Sample Preparations and Related Methods, First Edition. 

The abundance of a trace element is often too small to be accurately quantihed using conventional analytical methods such as ion chromatography or mass spectrometry. It is possible, however, to precisely determine very low concentrations of a constituent by measuring its radioactive decay properties. In order to understand how U-Th series radionuclides can provide such low-level tracer information, a brief review of the basic principles of radioactive decay and the application of these radionuclides as geochronological tools is useful. " The U-Th decay series together consist of 36 radionuclides that are isotopes (same atomic number, Z, different atomic mass, M) of 10 distinct elements (Figure 1). Some of these are very short-lived (tj j 1 -nd are thus not directly useful as marine tracers. It is the other radioisotopes with half-lives greater than 1 day that are most useful and are the focus of this chapter. 

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

Residue analytical methods for neonicotinoids in crops, soil and water samples have been developed. The basic principle of these methods consists of the following steps extraction of the crop and/or soil samples with acetone or the other organic solvent, cleanup by liquid-liquid partition or column chromatography, and quantitative analysis by high-performance liquid chromatography with ultraviolet detection (HPLC/UV). Simple column cleanup procedures are used to improve the accuracy and sensitivity of these methods. 

Both SPE and LLE involve a partitioning of compounds between two phases solid and liquid for SPE and two immiscible liquids for LLE. As modem SPE is a technique in which the basic principles of liquid chromatography are used to isolate the compound(s) of... 

Figure 6.17 Schematic representation of the basic principles of metal chelate affinity chromatography. Certain proteins are retained on the column via the formation of coordinate bonds with the immobilized metal ion (a). The actual structure of the most commonly used metal chelator, iminodiacetic acid, is presented in (b)...

Gas-Liquid Chromatography. In gas-liquid chromatography (GLC) the stationary phase is a liquid. GLC capillary columns are coated internally with a liquid (WCOT columns) stationary phase. As discussed above, in GC the interaction of the sample molecules with the mobile phase is very weak. Therefore, the primary means of creating differential adsorption is through the choice of the particular liquid stationary phase to be used. The basic principle is that analytes selectively interact with stationary phases of similar chemical nature. For example, a mixture of nonpolar components of the same chemical type, such as hydrocarbons in most petroleum fractions, often separates well on a column with a nonpolar stationary phase, while samples with polar or polarizable compounds often resolve well on the more polar and/or polarizable stationary phases. Reference 7 is a metabolomics example of capillary GC-MS. 

Liquid chromatography (LC) activated alumina applications, 2 400 adsorption, 1 610-611 of ascorbic acid, 25 760 basic principles, 4 603-606 classification of solvents for, 23 87... 

J0NSSON, J. A., in Chromatographic Theory and Basic Principles (Jonsson, J. A. ed.), Chapter 3, Dispersion and Peak Shapes in Chromatography (Marcel Dekker, 1987). 

In this chapter, we discuss the basic principles of modern liquid chromatography, which have been slowly and painfully recognized as valid over the past ten years. After presenting the main features of the optimization model together with the relevant equations, we shall point out the practical consequences of this approach and the way the analyst can use the optimization scheme in practice (5-26). 

In ion-pair chromatography, a great number of parameters influence the retention of a charged solute e.g., the type of solute, the type and the concentration of the pairing ion, the type and the concentration of the buffer, the mobile phase composition, etc. This makes ion-pair chromatography a versatile technique at the same time as it appears to be complicated and difficult to control. From the discussion above, it is clear that a few simple basic principles often can be used to understand the retention behavior when the experimental conditions are varied. In practical work, it may be desirable to make predictions of retentions from a limited set of retention data and without going into the more complicated theoretical models. For this purpose, an approximate equation was derived that considers most of the parameters in a simple and practically useful way. For the derivation of this simple version of the model and for a guide to its use and applicability, we refer to Ref. [8]. Here, we will only state the final equation and show one simple example of its use. 

Basic principles of Ion chromatography IC Module Navigation, The University of MACHIAS at MACHIAS. 

Headspace is a sampling device used in tandem with a gas chromatograph. It is used in the determination of volatile compounds contained in a matrix which does not lend itself to direct analysis by chromatography. The basic principle is very simple, as described in the following examples. 

The basic principles of adsorption, ion-exchange, and affinity resins have been explained in the previous section on adsorption. Chromatography is similar to adsorption because both involve the interaction between solute and solid matrix. However, they are different in a sense that chromatography is based on the different rate of movement of the solute in the column, while adsorption is based on the separation of one solute from other constituencies by being captured on the adsorbent. 

There are several types of chromatography however, they all follow the same basic principles. The simplest kind is paper chromatography. To separate the different-coloured dyes in a sample of black ink, a spot of the ink is put on to a piece of chromatography paper. This paper is then set in a suitable solvent as shown in Figure 2.26. 

Capillary Electrochromatography. Capillary electrochromatography (CEC) is a hybrid technique that works on the basic principles of capillary electrophoresis and chromatography [41], This mode of chromatography is used on either packed or tubular capillaries/columns. The packed column approach was introduced by Pretorius et al. [60] in 1974, while open tubular CEC was presented by Tsuda et al. [61] a decade later. In 1984 Terabe et al. [62] introduced another modification in liquid chromatography, micellar electrokinetic capillary... 

The static laser light scattering apparatus used as an on-line GPC detector has been popular for a while. Here, we illustrate another but less known method of combining the results from (gel permeation chromatography) and DLS. The basic principle is as follows There is a similarity between these two tools in that the translational diffusion coefficient D obtained by DLS and the elution volume V in GPC are related to the hydrodynamic size of a given macromolecule. In a first approximation, if the hydrodynamic size is proportional to the molar mass, we have... 

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