Principles and Specifications of Flash Chromatography Columns
Flash is a fast separation mode for preparative chromatography, which uses optimized pre-packed low and medium pressure columns for chromatographic separations. Flash is considered to be low- and medium-pressure separation chromatography, and its resolution is correspondingly lower than HPLC (high-performance liquid chromatography, or high-pressure liquid chromatography). As a unique chromatography technique that pushes solvent through the column uses by compressed gas or a pump, flash column chromatography is highly appreciated as an advance technique because it makes flow rates of the solvent much faster than the gravity flow.
Developed in the 1970’s, flash column chromatography was upgraded from long column chromatography technology in the lab. At that time, the scientists were tired of long column chromatography, because it’s kind of time-wasting with poor results. But flash column chromatography can not only provide better separation but also reduce the running time of the sample separations. The whole process usually takes about 5-10 minutes. Compared to traditional column chromatography, it is a fast and inexpensive technology. Flash separation and purification technology are now widely used in various applications such as drug development, sample purification, and natural product purification. Because of its low cost and simplicity, FLASH is one of the chromatography separation and purification tools that cannot be replaced by preparative HPLC.
The silica gel is not only the gel which was first used in the column, but it is widely employed still nowadays. The air was pressured to drive the solvent through the silica gel column and compress it. After the sample is applied, and the same solvent is used to pass the sample through the column. The solvent can be different sometimes. And then, it’s the time we can collect the purified component, small fractions emerge first, and the larger ones go after.
Principles of flash column chromatography
- Adsorption: Flash chromatography relies on the adsorption of compounds onto a solid stationary phase (typically silica gel or a similar material) inside a column. Compounds in the sample mixture interact differently with the stationary phase, leading to separation based on their affinity for the stationary phase.
- Elution: After loading the sample mixture onto the column, an eluent (solvent or solvent mixture) is passed through the column. This eluent carries the sample compounds through the stationary phase. Compounds with stronger interactions with the stationary phase move more slowly through the column, while those with weaker interactions move more quickly.
- Fractionation: The separated compounds are collected in fractions as they elute from the column. These fractions are typically collected in test tubes or other containers. Each fraction contains a group of compounds with similar elution properties.
- Detection: Flash chromatography is often coupled with detectors (e.g., UV-Vis or evaporative light scattering detectors) to monitor the elution of compounds in real-time. This aids in determining when to collect fractions containing the desired compounds
General specifications of flash columns
• The most commonly used filler for Flash is silica gel (most specifications are 40-63 60Å) because:
-Limited choice of packing materials for columns and TLC at the time.
-Other bonds and phases such as C8, and C18 are too expensive.
Therefore, most of the Flash application methods available in the literature are developed using silica gel as the separation matrix.
• Flash is basically normal phase liquid chromatography separation technology. There are also reversed-phase silica fillers; however, most users prefer flash technology to use silica gel.
• The typical loading scale is from milligrams to a hundred grams. The flow rate is from 10 mL/min to 300 mL/min.
• Use organic solvents of low to medium polarity as mobile phases such as hexane, ethyl acetate, etc.
Hawach quick-separation columns are packed with proprietary technology for automatic packing, and the column bed is compact and uniform without a “ditch flow effect”. High resolution and good reproducibility.
Different particle sizes (minimum 15 μm) of normal phase and reversed-phase silica packing can allow users to freely choose different fast separation columns in terms of resolution, sample volume, and flow rate according to different needs of the economy and performance.
The rapid separation column is made of medical-grade polypropylene (PP) material, which avoids the dissolution pollution of common PP materials on the separation sample. In addition, the transparent PP material cylinder allows the user to visually observe the separation of the sample. The patented column design allows the maximum separation pressure of the rapid separation column to reach 300 psi, and it is safe and leak-free.
Fast separation columns have Luer-Lock standard fittings and can be used on a variety of fast liquid chromatography separation systems.
