About The Development Of Flash Column
In 1978, Still invented flash chromatography, published in J.O.C, from which the flash method was established. Flash column is derived from open glass column chromatography and is mainly used for the separation and purification of natural products and organic synthesis products. The classical flash chromatogram consists of a glass column, a liquid storage bottle, and a compressed air regulating valve. With low cost, it is easy to observe, but the pressure is low and easy to break.
Many laboratories now place a pressurized ball on top of a glass column, which is a similar product and forms a classic flash chromatography system after improved. It consists of the infusion pressure tank, flows regulating valve, flashes pre-packing column and sample loading device. The equipment is compact, easy to use, with high pressure and high reproducibility. The classic flash chromatogram is still pressurized with air pressure, the pressure range is about 0-7 bar, the column length is about 15 cm, and the filler particle size is 40-60 Torr. The solid and liquid can be loaded and the fraction collected by hand.
Over 20 years of development, the flash column has been widely used as a conventional purification separation device. The narrowly defined flash column refers to a low-pressure short-column preparative liquid chromatography system that uses compressed gas to generate pressure and accelerate the elution rate of the mobile phase. The generalized flash column system refers to the medium-low pressure liquid chromatography system of all infusion methods.
Recently, because of the intensification of scientific research competition and the increase of laboratory labor costs, higher automation and separation speed are required, resulting in automated flash columns, chromatography pumps, detectors, automatic fraction collectors and workstations. Some also have a gradient elution system, a column switching system, and an automatic sample introduction system. The conditions can be optimized to achieve unmanned operation, which greatly reduces labor costs and speeds up development.
Flash column is used for preparation and has the following advantages:
1. Fast speed
Generally 1/8 of the separation time of the open column chromatography, saving time, slow decomposition of sample changes.
2. Large preparation amount
Compared with HPLC preparation column of the same diameter, at least twice as many samples can be obtained
3. Low cost
First, it is lower than HPLC; secondly, the solvent is saved compared with the glass column, and the silica gel column can be used multiple times, saving the amount of silica gel.
No special solvent treatment-samples can be loaded dry, no special training for operators.
The effect of the flash column depends mainly on the optimization of the elution solvent and the column loading effect. In the relationship between processing and preparing with HPLC, the following principles should be followed:
(1) When the flash column can be used, no HPLC is required;
(2) First, use the flash column, and then use HPLC to purify.
Other tips are:
1. First, use TLC to select the antisolvent and load
2. Use short and thick columns (diameter: length <=1:7)
Hawach flash column
Hawach has three series of flash columns:
StarFlash series: only silica gel column, divided into standard and advanced, advanced silica gel with higher purity and better quality.
DepuFlash series: Corresponding to silica gel and phase column, C18 (spherical and irregular), C8, NH2, CN, Phenyl, SAX, SCX, Diol, which are made for the general market.
Other Flash series: Corresponding to silica gel construction and phase column, C18 (spherical inlet and irregular domestic), C4, C8, NH2, CN, HILIC, aluminum oxide, etc. which are made for the high-end market.
The materials used are all medical grade PP, PE, with strong corrosion resistance and low impurity content.