The packed column is a column used in different separation methods such as gas chromatography, HPLC, SPE and distillation. A chromatographic device must include a distribution system that can exchange the solution between the mobile phase and the stationary phase. In a packed column, the stationary phase is present in the column and the mobile phase can move through it. The column contains so-called carrier material, which does not react with substances to which the stationary phase is attached. In a packed column, the carrier material is present as loose particles that are scattered across the column. Due to difference in shape, the particles can be random or arranged in the column.
Most columns have an internal diameter of between 0.1 to 500 mm, with a length of several centimeters to 4 meters. The internal diameter and length of the column depend on the separation method for which the column is used. Material
The column itself is made of stainless steel, glass or plastic. Glass is chosen over steel using unstable fabrics, and steel in high pressure measurements.
As a carrier material from a packed column, substances are often used as diatomaceous earth and silica (SiO 2 {\displaystyle _{2}} ). To minimize surface activity, the material is often washed with an acid to remove traces of iron and other metals. Then it is washed with water and acetone and dried. Thereafter, the material is treated with hexachlorodisilane to block remaining hydroxyl groups. The stationary phase is normally applied to the carrier material because it is dissolved in a suitable solvent which can be evaporated. Due to mechanical vibrations, the carrier material with the stationary phase is caught in the column.
The stationary phase can vary in polarity from very polar to highly apolar. In some cases, the stationary phase consists of one material, such as alumina or porous polymer. Use
A fluid through a packed column is much more resistant to a capillary column. With a capillary column, the carrier material with the stationary phase attached thereto is located on the inside of the column, creating large open space in the center of the column, allowing the mobile phase to flow.
On the other hand, there are many more binding sites in the packed column for the analyte in the mobile phase. As a result, the capacity of the packed column is greater than with a capillary column.
wiki
