Paper chromatography advantages

Paper chromatography has been used successfully for many years and is still a useful tool despite the fact that thin-layer techniques, especially with readily available commercially prepared plastic or foil-backed plates, offer advantages of speed, resolution and easier handling. Larger volumes of sample can be applied to paper, permitting the subsequent elution of a particular amino... 

Because polyphenolics show chemical complexities and similar structures, isolation and quantification of the individual polyphenolic compounds have been challenging. Many traditional techniques (paper chromatography, thin-layer chromatography, column chromatography) have been used. HPLC, with its merits of exacting resolution, ease of use, and short analysis time, has the further advantage that separation and quantification occur simultaneously. A reversed-phase HPLC apparatus equipped with a diode array detector makes possible the easy isolation and separation of many polyphenolics. For enhanced performance of HPLC separation, the polyphenolics should first be isolated into several fractions to effectively separate the individual polyphenolics (Jaworski and Lee, 1987 Oszmianski and Lee, 1990). 

Earlier studies of intracrystalline diffusion in zeolites were carried out almost exclusively by direct measurement of sorption rates but the limitations imposed by the intrusion of heat transfer and extra-crystalline mass transfer resistances were not always fully recognized. As a result the reported diffu-sivities showed many obvious inconsistencies such as differences in diffusivity between adsorption and desorption measurements(l-3), diffusivities which vary with fractional uptake (4) and large discrepancies between the values measured in different laboratories for apparently similar systems. More recently other experimental techniques have been applied, including chromatography and NMR methods. The latter have proved especially useful and have allowed the microdynamic behaviour of a number of important systems to be elucidated in considerable detail. In this paper the advantages and limitations of some of the common experimental techniques are considered and the results of studies of diffusion in A, X and Y zeolites, which have been the subject of several detailed investigations, are briefly reviewed. 

Despite several shortcomings, paper chromatography was clearly advantageous to qualitative analytical methods. One of the major advantages was its application in the quantitative analysis of flavonoids. This point is manifested by several reports using paper chromatography... 

AMP [20]. Paper chromatography offers the advantage that the content of ATP degradation products can be monitored. The spots are made visible under ultraviolet light, cut out, and placed in vials containing scintillation fluid for counting. Also, thin-layer chromatography has been used for the isolation of labelled cyclic nucleotides [101,102]. 

Classic paper chromatography like distribution chromatography is also carried out today in most cases in layers on a support sheet. To obtain low standard deviations extensive automatization from sample application to evaluation is necessary. The essential advantage in comparison to liquid column chromatography is the possibility of separating several samples side by side, because therefor usually no apparatus is required. 

Paper chromatography can be used instead of, or in 2-dimensional systems as well as, paper electrophoresis. Its principal advantage is that less expensive equipment is required and that some separations, particularly sequence-dependent ones, are difficult to obtain by paper... 

The preceding examples elegantly demonstrate the point at which zone electrophoresis may be used to advantage in structural determinations on polysaccharides, namely, in further resolving fractions isolated by carbon-Celite column chromatography or paper chromatography, or both. 

Paper chromatography has now, to a great extent, replaced alumina or similar absorbent columns. An advantage is that much smaller quantities can be used. The apparatus is illustrated diagrammatically in Fig. 25.13. The sheet of filter paper is suspended so that its bottom dips into a vessel containing the eluent and the upper end is attached by clips to a frame (Fig. 25.14). 

Paper chromatography is usually used for highly polar compounds such as sugars, amino acids and natmal pigments. Some advantages of paper chromatography are a small amount of sample is required, a high level of resolution, ease of detection and simphcity of the apparatus. 

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