GC Columns

                               GC Column Specifications

 1. Column Type

GC columns come in two main categories:

• Capillary (Open Tubular) Columns

  • Fused silica tubing with an internal stationary phase coating.

  • Provide high separation efficiency and sharp peaks. 

• Packed Columns

  • Filled with solid support (often coated with liquid phase).

  • Larger diameter, higher sample capacity, but lower resolution than capillaries. 

Example products

• Supelco Metal Packed GC Column metal packed GC column

• GC Packed Columns / Supelco Glass Packed GC Column glass/packed configurations

 2. Column Length

• Typical capillary lengths: 10100 m (30 m is a common standard). 

• Effect:

  • Longer higher resolution but longer retention times and higher backpressure.

  • Shorter faster runs with lower resolving power. 

 3. Internal Diameter (I.D.)

Common bore sizes for capillary columns:

• Smaller I.D. higher efficiency but lower sample load.

• Larger I.D. better for large volumes and wide bore applications. 

 4. Film Thickness (Stationary Phase)

• The liquid phase coating thickness is usually 0.105.00 m. 

• Effects:

  • Thin film (0.100.25 m) faster elution, good for high-boiling analytes. 

  • Thick film (>1.0 m) stronger retention of volatile compounds, higher capacity, but higher bleed at high temp. 

 5. Stationary Phase / Polarity

The chemistry of this phase determines selectivity:

Choosing polarity is based on how your analytes interact with the stationary phase (like dissolves like). 

 6. Temperature Limits

• Each stationary phase has a maximum temperature rating.

• Non-polar phases typically tolerate higher temperatures (e.g., up to 350 C), while more polar phases may be lower. 

 7. Compatibility & Fittings

Columns must match your GC systems fittings:

• Standard ferrule sizes and connector types (e.g., 1/8, 0.53 mm compatible).

• Detector compatibility (FID, TCD, ECD, MS).