Definitions for "Guard column"
a short, disposable segment of column located before the main column to trap difficult materials.
a small column placed between the injector and the analytical column. Protects the analytical column against contamination by sample particulates and, perhaps, by strongly retained species. The guard column is usually packed with the same material as the analytical column and is often of the same i.d. It is much shorter, costs less, and is usually discarded when it becomes contaminated. Guard column is only useful for preparative separations in any other cases it is just waste of money and decrease of the system efficiency. - Same as HETP.
a very short column that is introduced between the sample chamber and the analytical column