Interchim快速制备色谱仪上样量与色谱柱关系表

PuriFlash Column Loading Chart explanation
From TLC to Flashcartridges
In order to have a good selectivity in Flashchromatography, it is important to have a Rf (retention factor) value on the TLC plate between 0,15 and 0,35 or CVs of 2.8 to 6.7 Components with Rf values above 0.35 will elute too early
Components with Rf values below 0.15 will consume too much solvent
To know how to calculate a Rf value, see the second page.
In the PuriFlash Loading Chart we speak about CV
CV = 1/Rf
CV = CV A- CV B
CV = 1 to 1.5 = difficult
CV = 1.5 to 4 = standard
CV = 4 to 10 = easy
Example :
We would like to separate 1g of a mixture of two compounds
Compound A has a Rf of 0,25
Compound B has a Rf of 0,40
CV = 1/0. 25 –1/0.4 = 1.5
the separation is difficult, if we look in the chart, the yellow area displays difficult separation. For an among of 1g (1000mg) the appropriate cartridge would be a 200g Cartridge.
For an easy separation, a 40g cartridge is big enough to separate 1g of product.
Attention : this chart is a first, simple evaluation. It gives a first idea of loading capacity for a 50µm and irregular silica gel. If you use a 15µm for instance, in the case studied above we could try a 120g cartridge or perhaps even a 80g cartridges.
Calculation of the Rf value
The retention factor, R f, is defined as:
R f = distance the solute (D1) moves divided by the distance traveled by the solvent front (D2) = D1 / D2
R
where
D1 = distance that the compound traveled, measured
from center of the traveled point to where the
compound was applied
D2 = total distance that solvent traveled
0.15 < Rf < 0.35
∆Rf = Rf2- Rf1
∆Rf must be > 0,2
We speak as well about CV = Column Volume. CV is the number of column volumes required to elute the component from the column regardless of column dimensions.
CV = 1/Rf
∆CV = CV1- CV2
1 < ∆CV < 1.5 = difficult
1.5 < ∆CV < 4 = standard
4 < ∆CV < 10 = easy。