Paper chromatography principles

Principles and Characteristics Paper chromatography, which was developed in 1944 [10], is the simplest and cheapest form of chromatography and has been used... 

Thin layer chromatography is in principle similar to paper chromatography when used in the ascending method,... 

Thin layer chromatography is in principle similar to paper chromatography when used in the ascending method, i.e. the solvent creeps up the stationary phase by capillarity. The adsorbent (e.g. silica, alumina, cellulose) is spread on a rectangular glass plate (or solid inert plastic sheet). Some adsorbents (e.g. silica) are mixed with a setting material (e.g. CaSC>4) by the manufacturers which causes the film to set on drying. The adsorbent can... 

C. Paper Chromatography(Papyrography or Partography). In this method, filter paper is used as an adsorbent in lieu of materials used in chromatographic columns. Although the principle of selective adsorption by paper (such as papyrus) was known for centuries and... 

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. 

Background and principles Paper chromatography is a commonly used method for separation and identification of coloured compounds, including pigments. This technique relies on the separation of biomolecules from a mixture on the basis of partition, that is, difference in solubility and hence distribution of a given biomolecule between the stationary and mobile phase. 

Figure 7.2 Overview of key principles and methodology of separation by paper chromatography.

Background and principles Thin-layer chromatography is the other most commonly used form of planar chromatography and uses a very similar experimental approach to paper chromatography. The principal difference is that this technique relies on the separation of biomolecules from a mixture on the basis of partition and/or adsorption. There is a distinct difference between the process of adsorption and a/isorption, and they are not interchangeable terms Whereas molecules that are a/isorbed are taken up into , those that are adsorbed stick to a surface. So, in thin-layer chromatography, the mobile phase is adsorbed (sticks to) and subsequently moves along the stationary phase. The stationary phase consists of an adsorbent (sticky) layer on a flat plate or sheet. The most commonly encountered adsorbent layers comprise silica gel, alumina (not aluminium) or cellulose, while popular solvents include hexane, acetone and alcohol. 

Paper chromatography Has largely been superseded by more sophisticated chromatographic methods in bioanalytical laboratories however this method still remains an important teaching tool to illustrate basic chromatography principles and technique. It still retains value in sample identification using appropriate standards (controls), for example in amino acid analysis. 

Thin-Layer Chromatography. A few years after the introduction of paper chromatography, the principles of thin-layer chromatography were... 

A description of the principles of paper chromatography is not within the scope of this summary. Suffice it to say that the compounds to be separated have varying degrees of affinity for the cellulose fibers of the paper and differential solubilities in the solvent system used hence, different compounds will travel at different rates with relation to the rate of travel of the solvent. The ratio between the rates of travel of the solvent and the particular compoimd in question is constant under standard conditions and is designated the R/ of that compound ... 

The principles of paper chromatography are similar to those of column chromatography discussed in Chapters 14 to 18. The main difference is that a piece of paper is used for the inert phase. The solution to be examined is deposited as a small spot on the paper. The mobile phase is allowed to move over the spot in a definite direction, and the substances are separated by their differences in solubility in the moving solvent and the stationary phase, which generally is considered to be the water normally present in paper. Isaac Asimov, the well-known science fiction writer. 

Paper chromatography once played an important role in biochemical analysis because it provided a method for separating amino acids using very simple equipment. Although more modern techniques are now more commonly used, we will describe the principles behind paper chromatography because many of the same principles are employed in modern separation techniques. 

Thin layer chromatography (TLC) and paper chromatography (PC), which together comprise flat-bed or planar chromatography, are the easiest of all chromatographic methods to perform, and they require only simple and inexpensive equipment. Many of the techniques and principles of TLC and PC are the same. They both readily provide qualitative analytical information, and, with optimization of techniques and materials, can give quantitative data as well. 

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