Introduction to Flash Chromatography

Flash chromatography

Flash chromatography is one of the methods in the preparation of liquid chromatography and is usually used for the separation of organic compounds. Flash chromatography has the advantages of ease of operation, low cost, and fast analysis. Few other techniques can match flash chromatography for applications in the purification of organic compounds. Flash chromatography has become a versatile method for normal phase separation by purification.

Flash chromatography is a typical low-pressure technique, and scientists are using vacuum or pump technology to accelerate the separation of flash chromatography at medium pressure. The flash column is filled with a silica gel adsorbent with a particle size of 40-60 mm. A low-viscosity mobile phase requires a smaller particle size. Traditional flash chromatography requires scientists to fill the flash column as needed for testing, so many columns become disposable prefabricated columns.

Flash chromatography is often used to scale up to normal phase chemicals separated by thin-layer chromatography. The demand for flash chromatography comes mainly from the pharmaceutical industry, biotechnology, and academic institutions, which account for 84% of the market for fast chromatography. In the pharmaceutical industry, flash chromatography is used in a wide range of applications, including the purification of small amounts of compounds, peptides, and purification of natural products.

Flash Column Chromatography

Flash column chromatography is quite an easy and convenient way to separate very complex mixtures of compounds. It can satisfy most organic compounds’ purification requirements, no matter the synthetic mixture or the natural plant extract. You can inject the sample from several micrograms to several hundred grams. It will realize efficient separation under the pressure of 10 bar and satisfy all the purification requirements of flash column chromatography.

1. Functions

Satisfy all the purification requirements of flash column chromatography.
Monitoring by four wavelengths makes it efficient and time-saving.

2. Principle

The principles of flash chromatography are similar to other chromatographic techniques. The mixture to be separated is loaded onto the top of the column, and a solvent or solvent mixture is passed through the column. The compounds in the mixture interact with the stationary phase to varying degrees, leading to separation as they move through the column.

3. Features

As a new chromatographic system, it is mainly used for the separation and purification of a large number of complex organic mixtures, combinatorial chemistry, new drug development, or natural product research. It features high speed, large separation, good repeatability, high efficiency, and automation. Most of the sample separation can be completed in 30 minutes.

The system uses a chemically inert, maintenance-free gradient pump system that uses normal and reversed-phase solvents to operate at pressures up to 100 psi at flow rates of 5-100 ml/min. It can get rid of the traditional glass chromatography column with very low efficiency and meets the chemical synthesis of small-batch/medium batch or the separation and purification of natural products, which greatly improves the separation efficiency.

4. Highlights

a. Dissolution of impurities aspects: Because the materials used are all medical grade PP, and PE, with strong corrosion resistance and low impurity content, the probability of impurity dissolution is low.
b. There are many series to meet different demands. The adsorbent can be imported and domestic. What’s more, there are various specifications to make all customers satisfied whether they pay more attention to quality or price.
c. For the adsorbent particle size, users can refer to the particle size distribution curve provided by HAWACH, which is correct and convenient.

Flash Chromatography Column

The flash column can overcome the defect of the ordinary column’s separation. It has the advantages of being quick, time-saving, high efficiency of separation, and simple and practicable. As for samples of 0.01 to 10 grams and an Rf value of more than 0.15, they can be quickly separated within 10 to 15 minutes.


Neutral Alumina Flash Columns

  • The adsorbed stationary phases are normally silica gel and aluminum oxide. The required mesh numbers are 100 to 160 or above 160.
  • The lower of adsorbing agent’s mesh number is, the higher degree of separation will be. However, the elution rate will be relatively slower.
  • When there are great differences between the Rf values, you can load 30 mg/g of silica gel with a mesh number of 100 to 160. In more cases, 10 mg/g of silica gel is required.
  • When using aluminum oxide, the required mesh number is 100 to 150. 20 to 50 grams of aluminum oxide are needed to separate 1 gram of the sample.

Conditions and Procedures of Flash Column

  1. Choose the eluting agent with high separation efficiency on the TLC board.
  2. Choose an appropriate chromatographic column with silica gel with a mesh number of 230 to 400.
  3. After the eluting agent is added, quickly eliminate the air inside the silica gel under the pressure.
  4. After sample loading, elute and control the flow rate within 2.0 in/min.


Solvent Selection: The choice of solvent and its gradient play a crucial role in the separation of compounds.

Column Size and Packing: The column size and the amount of stationary phase used should be optimized for the sample load.

Monitoring: Monitoring the elution process is essential to collect fractions at the appropriate times.