Paper chromatography mobile phase selection

The following table provides a comprehensive guide to the selection of thin-layer chromatography media and solvents for a given chemical family. Mixed mobile phases are denoted with a slash, /, between components and where available the proportions are given. Among the references are several excellent texts,13 60 review articles,4 24 and original research papers and reports.25 59 6198 A table of abbreviations follows this section. 

Martin et al. published a paper on the theoretical limits of HPLC which is well worth reading.They used relatively simple mathematics to calculate pressure-optimized columns for which the length L, particle size and flow rate u of the mobile phase were selected such that a minimum pressure Ap is required to solve a separation problem. It has been shown that these optimized colunms are operated at their van Deemter curve minima. Some astonishing facts have emerged from the study, provided that the chromatography is performed on well packed columns (reduced plate height h = 2-3 see Section 8.5). 

Usualfy in paper chromatography the stationary phase is water since it is very well adsorbed by cellulose. TTie mobile phase, which is less polar flows over the polar stationary phase. The mobile phase may not be necessarily immiscible with water if water is being used as the stationary phase. This is because the stationary phase water is very tightly held by cellulose and will not mix with the mobile phase on this account. The mobile phase is usually a mixture of various solvents such as alcohols, acids, esters, ketones, phenols, amines, and hydrocarbons etc. The solvents are selected in such a way that the resolution of sample components Is satisfactory. 

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