What is pore size in HPLC column?
What is pore size in HPLC column?
As a general rule, a pore diameter of 10 nm or less should be used for analytes below 3,000 Da. A pore diameter of 10 – 13 Da is recommended for samples in the range of 3,000 – 10,000 Da. For samples above 10,000 Da, including peptides and proteins, a 30 nm material provides the best efficiency and peak shape.
What are the differences between C4 C8 and C18 columns in HPLC?
C18 has 18 carbon atoms while C8 has only 8 carbon atoms. C18 has a longer carbon chain, but C8 has a shorter one. C18 has higher retention while C8 has shorter retention. C18 has higher hydrophobicity, but C8 has a lower hydrophobicity….Follow Pharmaguideline.
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What does C18 mean in HPLC column?
C18 is octyldecylsilane and contains 18 carbons bound to the silica. So they have more carbons and a longer carbon chain than C8 (8 carbons) or C4 (4 carbons). Because of the extra carbons, C18 has a larger surface area that the mobile phase has to travel across.
Can you run 100% water through C18 column?
It is definitely not recommended to run a common C18 column with pure aqueous mobile phase. Because of their length the linked chains have hydrophobic properties and might collapse if used with 100 % water.
What affects pore size?
Skin type, which is also generally determined by genetics, is one factor that can influence the size of a person’s pores. People with oily skin tend to have larger pores while people with dry skin generally have smaller pores. This is also why many pores tend to be larger around the nose where skin is often oilier.
Why are HPLC particles porous?
Theory and experiments have clearly established that particles used for the HPLC separation of molecules should have pores that are sufficiently large to allow free movement of such molecules within the pore structure and not restrict diffusion [1, 2].
What is aqueous mobile phase?
The mobile phase is generally a binary mixture of water and a miscible polar organic solvent like methanol, acetonitrile or THF. Retention increases as the amount of the polar solvent (water) in the mobile phase increases.
What is the difference between HPLC and C18 columns?
HPLC columns separate any compound into its components and C18 columns are widely used in chemical analysis because these have some unique properties. Standards and success of any pharmaceutical company is determined by how professional chemical analysis are being undertaken.
Why is pore size important in HPLC?
Therefore, the pore size of the packing material in your HPLC column is important, since the molecules must ‘fit’ into the porous structure in order to interact with the stationary phase. Smaller pore size packings (pore size 80 to 120Å) are best for small molecules with molecular weights up to a molecular weight of 2000.
What is the surface area of a typical HPLC column?
A typical surface area of the silica used for chromatography is around 330m 2 /g and, in a 150 x 4.6mm column, there may be as much as 1.5 g of silica — meaning your everyday HPLC column has around the same surface area as an average tennis court!
What size pore size should I choose for my column?
Additionally, a variety of coating options offer more functions for your column. The pore size you want is based on the molecular weight of your compound. The smallest molecules should be less than 120Å. Polypeptides and compounds with several proteins should be about 200-400Å. Very high molecular weight proteins should be 1,000-4,000Å.