Column chromatography is one of the most important methods to separate and purify organic compounds, and adsorption column chromatography is the most widely used.
However, the above method is commonly taken under ordinary pressure. It is slow and time-consuming. When preparing, separating, or purifying organic compounds that are photosensitive and oxy-sensitive in large doses, rapid elution is extremely necessary. Here we will talk about barometric flash column chromatography.
Principle of Flash Column Chromatography
During the process of barometric flash column chromatography, exert pressure on the eluting agent in the column by filling the air. So that the eluting agent will flow faster and the operation time will be shortened.
Barometric Flash Column is a chromatography technology commonly used for the separation and purification of organic compounds. It is a variation of flash column chromatography characterized by the application of gas pressure to drive solvents and mixtures through the column during separation.
The following are the general working principles and steps of a barometric flash column:
Sample pretreatment: First, the mixture to be separated undergoes necessary pretreatment, which usually includes dissolution and cleanup. Packing the column: Select appropriate solid phase packing (such as silica gel, C18, etc.) and pack it into the column. Sample loading: Pass the pretreated sample solution through the column. Apply air pressure: Apply air pressure underneath the column, usually via a pressure vessel or an inert gas. This pushes the solvent and mixture through the column. Separation and elution: The components in the sample will be adsorbed and eluted in the column at different rates to achieve separation effects. Collect fractions: Collect the different components that elute, usually in the form of fractions.
Barometric flash columns have several advantages over traditional gravity-driven flash columns:
1. Faster: Applying air pressure can increase the speed of the separation process, especially for highly polar compounds or samples that are difficult to separate. 2. More controllable: By adjusting the air pressure, the speed and effect of separation can be more accurately controlled. 3. Suitable for specific samples: For some samples, air pressure drive may provide better separation results.
However, the following matters need to be noted when using a barometric flash column:
1. Make sure to use appropriate packing materials and conditions to avoid thermal sensitivity or chemical reactions of the sample. 2. Strictly control the air pressure to avoid damage to the column and packing. 3. Select the appropriate column and packing material based on the characteristics of the sample and the required purity. 4. Conduct sufficient experimental verification to ensure the reliability and separation effect of the method.
Instrument of Flash Column Chromatography
Barometric flash column, pump, filter flask, and test tube.
Procedures of Flash Column Chromatography
1. Choose a proper barometric flash column according to the volume of samples that are prepared to be separated. Add a little degreasing cotton, quartz sand, and adsorbing agent successively after the column is dried and cleaned up. Cover the upper layer of the adsorbing agent with quartz sand afterward. 2. After the preparatory work is finished, slip the rubber plug with the duct into the upper end of the barometric flash column, and connect the other end of the duct to the filter flask with a pump. Operate the pump to increase the pressure inside the column and the flow rate of the eluting agent is also increased.