Flash column chromatography is an easy and fast method to separate the complex mixtures. It can not only make the separation effect better but also shorten the time. How to put the sample into the flash column is of high importance in the preparation process of flash column chromatography. There are mainly three methods introduced below for the operators to select.
Pure Sample Method
The pure method is the easiest way if the sample is a non-viscous oil sample. The operator could use a long dropper filter to introduce the sample into the column first. And then, to rinse it with a predetermined solvent system, which would finally make all of the sample components flow into the column. However, it may cause a fault phenomenon in the column.
The solution method is more suitable for the liquid and solid sample by dissolving them in the solvents in the first stage and adding all the solutions to the flash column. The operator can choose the solvent that only moves one compound in the mixture samples or simply use the selected eluent. Nevertheless, there will be a risk when it comes to separation or purification with higher difficulties.
Silica Gel Adsorption Method
This method is available for some liquids and all the solid samples, which could adsorb the compound onto silica gel when employing the silica gel flash column. The silica gel is acidic, which destroys some acid-sensitive compounds. Therefore, these compounds usually require regeneration on a silica gel column.