GC Columns -

GC Columns

Category:

Producer:

Packed columns

Construction:

A metal (like stainless steel) or glass tube, typically 1-5 meters long and about 5 mm in inner diameter.
Stationary Phase:

Filled with a solid support material coated with a viscous liquid stationary phase, or sometimes a solid adsorbent.
Characteristics:

Capable of handling larger sample volumes and are specified for certain methods. However, they often produce broader peaks and lower separation efficiency compared to capillary columns.
Use Case:

Suitable for specific applications like fixed gas analysis.

Capillary columns

Construction:

A very long (10-100 m), thin tube made of fused silica glass with a protective polymer coating.
Stationary Phase:

The stationary phase is coated as a thin film on the inner surface of the tube.
Characteristics:

Offer superior separation efficiency, higher resolution, and sensitivity due to the thin coating. They have a lower sample capacity and require more concentrated samples or a split.
Use Case:

The most common type for most modern applications, ideal for trace analysis.

Common components and principles

Stationary Phase:

The substance inside the column that separates the sample components. Examples include non-polar polysiloxanes or more polar polyethylene glycols. The choice of stationary phase is crucial for separating different types of compounds.
Mobile Phase:

An inert carrier gas (like helium, nitrogen, or hydrogen) carries the sample through the column.
Separation Process:

As the sample travels through the column, each component interacts with the stationary phase to varying degrees based on its properties (like boiling point and solubility). This causes components to elute (come out of the column) at different times, allowing for separation and detection.

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