What is the difference between PTFE and silicone septa?
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What is the difference between PTFE and silicone septa?

Nov. 6th, 2023
Laboratory equipment and consumables play an essential role in ensuring accurate, reproducible scientific experiments. Septa are essential components for sealing containers such as vials to avoid contamination while protecting samples' integrity from spillover. Two commonly used materials for septa are Polytetrafluoroethylene (PTFE) and silicone; each has unique properties and applications - this article explores these differences so you can make informed choices when selecting your lab supplies.

Material Composition

PTFE Septa:

PTFE, more commonly known by its brand name Teflon, is a synthetic polymer composed of tetrafluoroethylene that has become renowned for its non-reactive and non-stick properties, making it ideal for laboratory applications. Our pure virgin PTFE septa are inert and highly resistant to chemical reactions - ideal materials for laboratory environments!

Silicone Septa:

Silicone septa are made of silicone rubber, an adaptable synthetic compound composed of silicon oxide, carbon monoxide and hydrogen atoms. Silicone rubber is well known for its resilience, making it a top choice in lab settings.
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Chemical Compatibility

PTFE Septa:

One of the primary advantages of PTFE septa is their exceptional chemical resistance. They are inert against most acids, bases, and organic solvents - an invaluable feature that makes them suitable for a range of analytical applications where samples may come into contact with various substances.

Silicone Septa:

While silicone septa are generally chemically inert, their versatility may not match up to that of PTFE septa. Silicone can swell or degrade when exposed to certain organic solvents and strong acids limiting its use to applications with less reactive substances.

Temperature Range

Temperature Range for PTFE Septa:

PTFE septa offers a broad temperature range, enabling it to function effectively even under adverse conditions. These flexible membranes can withstand both extreme high and low temperatures and are therefore well suited for applications that demand temperature stability.

Silicone Septa:

Silicone septa can also provide excellent temperature range performance, though they may not stand up as well against very high temperatures than their PTFE counterparts. They should meet most laboratory temperature needs.
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Permeability in PTFE Septa:

PTFE septa are designed with low permeability to provide an effective seal against gases or other contaminants passing through, making them perfect for applications that need sample protection against external influences.

Silicone Septa:

Silicone septa have moderate permeability, making them unsuitable for applications where sample integrity is of primary concern; however, they are sometimes used when some gas exchange can be tolerated, such as headspace sampling.

Eager to learn all about PTFE and Silicone Septa? Check out this informative article:Everything You Need to Know:137 Pre-slit PTFE/Silicone Septa FAQs


Cost for PTFE Septa:

Due to their superior chemical resistance and other desirable properties, PTFE septa are generally more costly than silicone septa; however, their higher costs often justify themselves when used for critical laboratory applications.

Silicone Septa:

Silicone septa are more economical and practical choices for laboratory work that does not involve chemical compatibility or temperature extremes as major concerns.


Deciding between PTFE and silicone septa depends entirely on your laboratory application needs. When considering chemical resistance, temperature stability, sample integrity requirements or sample integrity concerns - PTFE septa are often preferred; on the other hand, silicone septa can provide more cost-effective options when used for routine laboratory procedures where their lower chemical resistance won't cause issues.

Understanding the differences among septa materials is essential to selecting one that ensures accuracy and success for your experiments. Consult your laboratory staff or suppliers in making an informed decision that suits both your research goals and budget.

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