Answer to Question #132497 in General Chemistry for hi

Question

How do you select a stationary phase for a given sample?

Answer 1

you should choose a stationary phase with similar polarity characteristics to those of the sample components. For example, higher polarity of the stationary phase will increase the selectivity of the cartridge for the polar components in the sample.

But when solvent modifications don’t help on a seemingly adequate phase, the only solution is mostly go for another stationary phase.

There is a big variety of stationary phases available on the cartridge/column market. These are the stationary phases mainly used in flash and prep chromatography:

• Silica has a high polar surface, it is the most popular stationary phase, ideal for conventional applications

• C18 has a non-polar surface, ideal for peptides and proteins

• Amino has a medium polar surface, ideal for carbohydrates and nitrogen containing heterocycles and amines

• Diol has a low polar surface, ideal for lipids

• Alumina has a high polar surface, ideal for acid sensitive compounds