Circular-paper chromatography in qualitative analysis

Abstract

Describes procedures for and examples of circular-paper chromatography.

Paper Chromatography for the Secondary Schools: I. The Analysis of the Common Cations

“…The Rfc value, which is the ratio of the distance from the initial spot to the center of gravity of each zone to the distance from the initial spot to the solvent front, is dependent upon various factors such as: the grade and quality of paper used, the temperature, pH, solvent system used, length of development, humidity, etc. (1,2,6,15,18). Hence, these values as published in literature are empirical and can be duplicated only if all the specified conditions in the experiment are fulfilled.…”

“…These exercises will be found to be quite stimulating and challenging to the pupil. Herewith are described experiments utilizing the simple circular or radial chromatographic technique of Brown (5) and Rutter (6) which has been extended by other investigators (7)(8)(9)(10)(11)(12)(13)(14)(15)(16). This technique is easily mastered and the results obtained can be readily interpreted by the method of direct comparison to a "known^which is run simultaneously with the sample being investigated (14).…”

“…Literature lists many solvent systems which have been used successfully to resolve the common cations (1,2,3,4,15). Some investigators follow the conventional qualitative analytical schemes; while others have classified the cations into chromatographic groups based upon the separation of these cations by means of selective solvents (1,7).…”

“…Some investigators follow the conventional qualitative analytical schemes; while others have classified the cations into chromatographic groups based upon the separation of these cations by means of selective solvents (1,7). Since most chemistry instructors are more familiar with the classification of the cations according to the conventional sulfide qualitative analytical scheme, solvent systems which will successfully separate the cations of Groups I, II, and III are presented in Tables 1-5 (15).…”

“…Reveal the resolved cations by means of a suitable chromogenic reagent by one of the techniques previously mentioned. 15. Measure the Rfc^s.…”