Paper chromatography horizontal

Figure 11.22 represents a paper electrophoresis apparatus. The soaked cellulose sheet is sandwiched between two horizontal glass plates with the ends dipped into vessels containing more electrolyte solution. The electrodes are also dipped into these vessels, as shown. The sample is spotted in the center of the sheet, and the oppositely charged ions then have room to migrate in opposite directions on the sheet. Qualitative analysis is performed much as with paper chromatography, by comparing the distances the... 

The different methods of arranging the filter paper in the chromatographic chamber have been applied to sugar separations descending, ascending,39 40 and circular or horizontal development.41 These methods and other techniques will be discussed below. Detailed descriptions of the equipment needed for paper chromatography are readily available.8... 

There are several types of paper chromatography, and they are named according to the direction the mobile phase flows through the paper. These are ascending, descending, horizontal, and two-dimensional, and any of these with a reversed phase. 

The apparatus used for continuous-flow paper electrophoresis can be used for separation with an elution rather than a continuous-flow method. The sample is spotted at the top of the paper and only the buffer solution is continuously added. If the electrophoresis is stopped before the sample components drip from the bottom of the paper, the technique combines the separating ability of descending paper chromatography (separation occurring vertically) with that of electrophoresis (separation occurring horizontally) to yield spots simultaneously developed in two dimensions. 

Paper chromatography, transition metals, ascending and horizontal development. 

The solv ent migration rate can be accelerated through centrifugal force. The plate and layer are rotated in a horizontal plane and solvent introduced at the axis of rotation. Rosmus, PAVLf EK and Deyl [585], who had previously studied centrifugal paper chromatography in detail, have tried out the technique with TLC. They showed that the Stahl test mixture and mixtures of 2,4-dinitrophenylhydrazones could be separated in 5—10 min on silica gel G layers of 20 cm diameter, using 500 revs/min. 

Another type of apparatus with nonhorizontal strip has been described by Michl (1951). It is made of a glass cylinder of the type used in paper chromatography in which one electrode is applied in the trough and the other in the bottom of the cylinder. Recently Michl (1952b) described an apparatus vrith horizontal strip in which the paper lies between insulated aluminum coolers. 

Obtain a 25 X 16-cm piece of Whatman 1 chromatography paper or filter paper. Take precautions to keep the paper clean. Only touch the edges with your fingers, and lay it on a clean paper towel on the bench top. Using a pencil, draw a horizontal line across the paper at a distance of 2.5 cm from one edge, as shown in Figure 16.15. Also draw short vertical lines at 3.5-cm intervals across the horizontal lines, as shown. The intersections of these lines are where the sample spots will be applied. Also label each intersection as shown. 

Figure 10.6. Developing chambers for plane chromatography (a) descending— used with PC (b) ascending—used with TLC and PC (c) sandwich—used with TLC (d) horizontal—used with paper as shown, but also adaptable for HPTLC.

Developing chambers for horizontal development were originally conceived as sandwich chambers (S-chambers) in which the plate, with the layer imdemeath, is placed above the counter-plate at a distance of 0.5 mm. Without this counter-plate, a filter paper soaked in solvent can be placed at the bottom of the chamber, enabling development to be performed in a saturated chamber. Chromatography can be performed with only a few ml solvent in horizontal chambers, which is, of course, economic and reduces disposal problems. However, the question arises how much of a four- or five-component solvent system is actually used if only 2 ml is consumed in the development process in the 5 x 5 cm horizontal chamber ... 

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