N N x RF

N' is called the bed efficiency, or the number of hypothetical theoretical plates observed with an inert solute. The Snyder equation is thus written:


Neglecting the variable density of the liquid phase along the plate due to the wide distribution of pore size in the TLC bed, the retardation factor is related to the bed capacity factor through where k is the retention factor (see HPLC).

The actual relationship is more complex because Rf is somewhat dependent on the experimental conditions, an effect which is neglected as a first approximation. Chromatographers use either RF or k, depending upon whether they are interested in column or thin-layer chromatography. The parameter a, the relative retention of the two consecutive solutes of interest is given by:

From this equation it is impossible to achieve any resolution when RF is 1 or 0. Figure 1 shows a plot of the variation of resolution, RS, with RF. A maximum is observed when RF = 0.33. However, within the range 0.20-0.50 no dramatic loss of resolution occur as 92% of the maximum efficiency is reached. It is essential to select a solvent that gives an RF value somewhat larger than 0.33 for the two solutes to be separated, in order to achieve the analysis within a reasonable time.

Rewriting eqn [10] in a more convenient form yields:

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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