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In chromatography, the retardation factor (R) is the fraction of an analyte in the mobile phase of a chromatographic system. [1] In planar chromatography in particular, the retardation factor R F is defined as the ratio of the distance traveled by the center of a spot to the distance traveled by the solvent front. [ 2 ]
The [N 1/2 /4] term is the column factor, the [(α-1)/α] term is the thermodynamic factor, and the [k 2 '/(1+k 2 ')] term is the retention factor. The 3 factors are not completely independent, but they are very close, and can be treated as such. So what does this mean?
Retention uniformity is calculated from the following formula: = (+) (+) = (+) where n is the number of compounds separated, R f (1...n) are the Retention factor of the compounds sorted in non-descending order.
Example chromatogram showing signal as a function of retention time. In chromatography, resolution is a measure of the separation of two peaks of different retention time t in a chromatogram. [1] [2] [3] [4]
The retardation factor (R f), or retention factor, quantifies the results. It is the distance traveled by a given substance divided by the distance traveled by the mobile phase. [citation needed] Development of a TLC plate. Spots that appear purple separate into red spots and blue spots.
In gas chromatography, the Kovats retention index (shorter Kovats index, retention index; plural retention indices) is used to convert retention times into system-independent constants. The index is named after the Hungarian-born Swiss chemist Ervin Kováts , who outlined the concept in the 1950s while performing research into the composition ...
This factor is defined in terms of a ratio of the retention factors of a pair of neighboring chromatogram peaks, and may also be corrected for by the void volume of the column. The greater the separation factor value is over 1.0, the better the separation, until about 2.0 beyond which an HPLC method is probably not needed for separation.
The Purnell equation is an equation used in analytical chemistry to calculate the resolution R s between two peaks in a chromatogram. [1] [2]= (′ + ′) where R s is the resolution between the two peaks