Septa Selection Guide

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There are many different types of materials used to produce the septa for LC and GC vial caps. 
Choosing the right septum for your application will help you to optimise performance and results. Here is a guideline to help you match the right products to your needs:

PTFE

  • Exceptional solvent resistance
  • Only suitable for single injection use - not recommended for sample storage before or after injection
  • NOT resealable
  • Maximum service temperature: 260°C

Silicone/PTFE

  • Excellent resealing capabilities
  • Autoclavable and excellent resistance to coring
  • PTFE chemical resistance until pierced then the septa will have the compatibility of silicone
  • Temperature range: -40°C to 200°C
  • Recommended for:
    • √ Multiple injections
    • √ Sample storage

Pre-slit PTFE/Silicone

  • Reduces the possibility of coring with blunt tipped needles or for applications using a thing gauge needle
  • Used to prevent vacuum from forming inside the vial
  • Temperature range: -40°C to 200°C
  • Recommended for:
    • √ Applications using thin gauge or blunt-tipped needles

PTFE/Silicone/PTFE

  • Recommended for multiple injections due to above average resealing capabilities
  • Autoclavable and excellent resistance to coring
  • Temperature range: -40°C to 200°C
  • Recommended for:
    • √ Multiple injections due to above average resealing capabilities
    • √ Demanding applications such as internal standards, trace analysis
    • √ Applications with a long time between injections.

Red Rubber/PTFE

  • Easy to pierce with moderate resealability
  • PTFE chemical resistance until pierced then the septa will have the compatibility of rubber
  • Not recommended when retaining samples for further analysis or for multiple injections
  • Temperature range: -40°C to 110°C
  • Recommended for:
    • √ Routine analyses

Moulded Polypropylene

  • Only suitable for single injection use - not recommended for sample storage before or after injection
  • Not resealable
  • Temperature range: 0°C to 130°C
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Omega Scientific is poised to support your chromatography needs. To browse our selection of vials, caps and inserts, click Vials and Accessories.
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