You can figure out that the longer and narrower columns will provide more theoretical plates, and slow the flow rate at the same time. And the resolution is also affected by the stationary phase. If the stationary phase or the gel which lines the column is more homogenous and has smaller particle size as well, you can get better resolution. Smaller particle size which means more surface area leads to a better resolution.
It’s very complex to control all these factors to optimize purity and recovery of components because the factors work with each other, but have different effects if tested individually. You can find mobile phase selectivity has the largest effect on the resolution, but it depends on the column capacity as well. the solvent that you choose can affect the resolution too.
The flash column chromatography has been widely used in organic chemistry since its advent. However, there are still some problems when using the method. The increasing sample size will result in a lower resolution. The best velocity depends on the length and width of the column and the properties of the gel. The resolution is affected by the stationary phase.
How does Flash column work
The working principle is the same as the liquid chromatography separation by selective adsorption and selective elution. The frequent used method is to pass the liquid sample solution through the adsorbent, retain the substance to be tested, and use the appropriate strength solvent to wash away the impurities, and then quickly elute the test substance with a small amount of solvent, thereby achieving the purpose of rapid separation, purification, and concentration. It is also possible to selectively adsorb the interfering impurities and let the measured substance flow out; or simultaneously adsorb the impurities and the tested substance, and then selectively elute the test substance with a suitable solvent.