GC Septa

GC septa are specialized components used in gas chromatography (GC) to seal the injection port while allowing a syringe needle to pass through to inject a sample into the system. They are small, disc-shaped, and typically made from materials such as silicone, PTFE (polytetrafluoroethylene), or a combination of both.

Key Features of GC Septa

• Chemical Resistance: Made from materials resistant to chemical degradation, particularly from solvents and sample components.
• Thermal Stability: Designed to withstand the high temperatures of the GC injection port, which often range from 200°C to 300°C or higher.
• Resealability: The septa reseal after the syringe needle is withdrawn, maintaining a tight seal to prevent gas leaks.
• Low Bleed: High-quality septa minimize contamination by releasing very low levels of volatile compounds into the carrier gas stream.

Types of GC Septa

• Pre-slit septa: Have a small cut that reduces coring (when fragments are cut out by the syringe needle) and prolongs septum life.
• Non-slit septa: Provide a better seal but may require more force to puncture and may wear out faster.
• High-temperature septa: Specifically designed for applications involving very high injection port temperatures.

Applications

• Analytical laboratories for routine sample injections.
• Environmental analysis, pharmaceuticals, food and beverage testing, and other fields requiring precise and contamination-free sample introduction.