Paper chromatography radial

The use of annular cylindrical beds, fed through a central channel and drained at the periphery, is of potential interest in cases where high throughput rates and wide but shallow beds are desired. Radial-flow geometry is also characteristic of one operating method used in paper chromatography. 

The range of development techniques available in paper chromatography is similar to those employed in TLC, namely, ascending, descending, radial. 

In addition to cellulose papers, modified-cellulose papers and glass-papers are also used for specific purposes. It is difficult to decide whether some self-supporting layers such as micropore membrane filter sheets or powders held in glass-paper sheets should be included among papers or thin layers. Paper chromatography is carried out in a descendant, ascendent or radial (circular) fashion. The diversity of the technique and the innumerable purposes to which it can be applied are discussed fully by textbooks and bibliographies, to which the reader is referred. 

The largest difference in Rt values for various rare earth pairs was observed when relatively concentrated nitric acid was used to elute the rare earths. The individual rare earths were detected by spraying the papers (after drying) with 8-hydroxyquinoline or Arsenazo I. Sub-microgram amounts of the individual rare earths could be detected and the separation of up to five rare earths was accomplished ip less than an hour by radial chromatography. 

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