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.
What is a C18 reversed phase column?
A C18 column is an example of a “reverse phase” column. Reverse phase columns are often used with more polar solvents such as water, methanol or acetonitrile. The stationary phase is a nonpolar hydrocarbon, whereas the mobile phase is a polar liquid. The same approach can also be used in TLC.
What is the difference between C8 and C18 HPLC columns?
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.
Is C18 normal phase?
More specifically, straight-chain alkanes are well-suited to serve as a good stationary phase. We should note that as the carbon atoms in the chain increases, the physical properties of the hydrocarbon changes as well—C1 through C4 are gaseous; C5-C17 are liquid; C18 and larger are solids.
What is the difference between C4 and C18 column?
C4 is generally used for proteins and C18 is generally used to capture peptides or small molecules. The idea here is that the larger protein molecule will likely have more hydrophobic moieties to interact with the column and thus a shorter chain length is more appropriate.
How are C18 columns made?
The C18 columns/cartridges in my lab are prepared using aqueous solvents, then organic solvents, then back to aqueous solvents (usually a combination of water, methanol and acetonitrile). I use the same procedure for both Reverse-Phase HPLC columns and Sep Pak cartridges.
How does C18 column work?
C18 simply means that the molecules contain 18 carbon atoms, so the other atoms in the molecule can vary, leading to significantly different substances. Knowing the characteristics of the compounds that will be run through the C18 columns can help you choose which one will work best for you.
What is the difference C8 and C18 HPLC column?
What is the difference between C8 and C18 HPLC columns? C18 has 18 carbon atoms while C8 has only 8 carbon atoms. C18 has a longer carbon chain, but C8 has a shorter one.
Which are columns used in HPLC?
The company’s columns are highly versatile, used for a broad set of applications ranging from food and beverage to biofuel analysis. “The addition of Benson Polymeric’s product suite to the Calibre Scientific portfolio presents interesting growth opportunities for both businesses,” said Ron Jones, President of Concise Separations.
How to optimize column efficiency in HPLC?
Silica based columns
How to choose HPLC column?
Column choice: Based on your sample and separation goals