Using The Right Mesh Size Of The Silica Gel For Column Chromatography

  • Date:Monday, Nov 27, 2023
Using The Right Mesh Size Of The Silica Gel For Column Chromatography

SiO2 is one of the most suitable and widely used adsorbent materials that is used in numerous chromatography applications and processes, for its high absorbency properties, supremely porous structure, and inert feature, especially in column chromatography techniques.

Silica gel is commonly used in the stationary phase of the column chromatography technique. It is a porous material with a high surface area, which makes it ideal for adsorbing and separating different types of molecules from a mixture effectively, and also aids in the purification of certain compounds from any contaminants and other mixtures present.

The mesh size of the silica gel for column chromatography refers to the size of the particles that make up the material and the pore structure that constitutes its amazing properties to adsorb or separate various compounds when passed through the column. Smaller mesh sizes generally indicate smaller particles, while larger mesh sizes indicate larger particles or pore structures.

The smaller mesh size which essentially means the material has a higher mesh number leads to a slower flow rate resulting in a higher resolution in the separation process of any mixture. This is because the smaller particles make it more difficult for the solvent to pass through, and they also have a higher surface area, which allows for more interaction between the solvent and the sample molecules.

The bigger the mesh size, the smaller the mesh number, which means that the flow rate is faster, and the smaller the size of the particles such as contaminants and other unnecessary compounds can flow through easily. Larger particles create a smoother flow for the solvent, and smaller particles have a smaller surface area, so they don't interact as much with the sample molecules.

The choice and usage of a particular silica gel mesh size for a certain type of column chromatography separation depends on a number of factors, including the type of sample that is being separated, the desired resolution that is to be achieved, and the flow rate required.

Generally, smaller mesh sizes mean higher-resolution separations, and bigger mesh sizes mean faster separations. But, higher resolution separations typically require longer run times, while faster separations typically have a lower resolution.

Common Silica Gel Mesh Sizes And Their Applications In Column Chromatography

There are different silica gel mesh sizes that can be used across different column chromatography techniques, which serve a specific purpose for the identification, separation, and purification of various compounds and mixtures.

Mesh size 60-120

The coarse mesh size of silica gel adsorbent material is highly porous in nature, and a great suitable stationary phase material for low-pressure column chromatography, flash chromatography, and gravity column chromatography. It is a great option for isolating a wide range of compounds from a particular mixture, and can be used from moderately polar to non-polar substances effectively.

For high performance and better results, you can pack the column well with this high-purity silica gel variety mesh size, to achieve the best results. They are also one of the most economical silica gel options for open column chromatography and gravity chromatography.

This mesh size of silica gel is easier to handle and provides the highest purity levels in chromatography processes. It offers the lowest humidity content, the smallest particle size distribution, and the lowest number of impurities in the silica gel mesh varieties. This size variety is the most commonly used silica gel mesh for chromatography processes.

Mesh Size 40-63

This mesh size of silica gel is widely used in the column chromatography process, as it has a high flow rate as well as a low resolution. That's because the big particles make it easier for the solvents to flow through. Plus, they have a smaller surface area, so the solvents don't interact as much with the sample molecules.

They are best for the Flash chromatography & low to medium-pressure preparative chromatography processes since they are far more easier to pack into the column during the stationary phases, and also provide a more uniform packing of the column. They have high resolutions, and can work and process complex mixtures and compounds during the chromatography process to identify, isolate, and purify the various compounds.

You can use this mesh size to purify raw and crude reaction mixtures that may contain a mixture of organic compounds with varying polarities that need to be separated or purified. During the column chromatography process, the lower polar compounds will be eluted first, then the higher polar compounds.

It can be used to isolate natural products, such as plant extracts and essential oils from a particular mixture, where the natural products are typically adsorbed onto the silica gel material surface and then eluted with a solvent that is appropriate for the polarity of the compounds contained in the mixture and need to be separated.

It is a great choice and widely used to effectively decolorize solutions by adsorbing colored impurities and used to decolorize solvents, oil mixtures, and other synthetic applications.

Mesh Size 230-400

This mesh size is usually used for high-resolution separations, like for preparative HPLC, thin layer chromatography, or analytical HPLC. This mesh size has a low flow rate and a high resolution. It's because the small particles make it more difficult for the solvent to pass through. They also have a bigger surface area, which means there's more interaction between the sample molecules and the solvent.

It makes a great option and can be used as a stationary phase material for thin layer chromatography techniques, or large scale process chromatography to purify amino mixtures, and other active compounds.

Preparative HPLC chromatography is a high-resolution separation technique that is used to purify large quantities of materials and mixtures, and this silica gel variety provides the highest resolution for preparative HPLC separations, but it also has the slowest flow rate. It can be used in analytical HPLC techniques to identify and separate small amounts of compounds. It is well-suited for preparative HPLC, analytical HPLC, and high-resolution flash column chromatography.

Tips For Choosing The Right Mesh Size For Column Chromatography

  • When choosing the suitable mesh size for your column chromatography process, keep in mind the type of column chromatography that is being performed and the desired end result that you want to achieve. For example, gravity column chromatography typically uses silica gel with a mesh size of 60-200 mesh, while flash column chromatography typically uses silica gel with a mesh size of 230-400 mesh.
  • You may want to consider the polarity of the sample compounds when separating or purifying the compounds to make sure the chosen silica gel mesh size is capable and has the right affinity to the particular compounds. Since, more polar compounds will interact more strongly with the silica gel surface, so a smaller mesh size may be required to achieve good resolution.
  • Make sure to use smaller or finer mesh sizes that will result in higher resolution and purity levels of the separation of different compounds, but also consider that they will also have slower flow rates.
  • The mesh size you choose depends on how big and complicated your sample is. If you're dealing with a big sample or a complicated mix, you might want to go with a coarse mesh to keep your flow rate steady. On the other hand, if you're dealing with smaller, more difficult samples, you might need to go with a finer mesh.

With column chromatography, there’s always room for improvement, so don’t be afraid to try new mesh sizes and optimize to find the right conditions for your particular separation. Keep in mind these careful considerations of various factors to choose the right mesh size of the silica gel for column chromatography