When conducting air sampling—particularly for the analysis of volatile organic compounds (VOCs)—choosing the right sampling material is essential. A commonly used option is the Tedlar bag. But are these gas sampling bags truly suitable for collecting VOCs? In this article, we take a closer look at the properties of Tedlar bags and explain why this material is used worldwide for VOC analysis.
What are VOCs?
Volatile organic compounds (VOCs) are chemical substances that easily evaporate at room temperature. They are found in solvents, fuels, paints, cleaning agents, and even exhaled breath. Because VOCs can affect health, air quality, and process safety, reliable sampling is crucial.
Properties of Tedlar Gas Sampling Bags
Tedlar bags are made from polyvinyl fluoride (PVF), a material developed by DuPont. This film has several unique properties that make it suitable for VOC sampling:
- Chemical resistance: Tedlar is inert and hardly reacts with organic compounds.
- Low permeability: Prevents VOCs from escaping or ambient air from entering.
- Thermal stability: Suitable for a wide temperature range (approximately -72°C to 107°C).
- Transparency and flexibility: Allows for visual inspection of the sample and facilitates transport.
VOC Sampling with Tedlar Bags
Tedlar bags have been used worldwide for decades to collect VOCs in both laboratory and field environments. They are suitable for sampling compounds such as:
- Benzene, toluene, xylene (BTX)
- Formaldehyde and acetone
- Terpenes and aldehydes
- Various solvents
These bags are compatible with common analytical methods like GC-FID, GC-MS, and HPLC, provided that the sample is analyzed within a limited time window (ideally within 24 to 72 hours, depending on the compound).
We have compiled an overview of various gases and their stability in different sampling bags, including Tedlar, on the following page:
Stability of samples in gas sample bags
Important Considerations When Using Tedlar for VOCs
Although Tedlar bags are very suitable for VOC sampling, there are some important considerations:
- Adsorption of polar substances: Some highly reactive or polar VOCs (such as aldehydes or amines) may partially adhere to the bag material. In such cases, other materials like Multi-Foil or Kynar may be more suitable.
- Sample storage time: VOCs do not remain stable indefinitely in Tedlar. Ensure that samples are analyzed as soon as possible.
- Fitting quality: Use high-quality fittings (such as PTFE or stainless steel) to prevent contamination or leakage.
Conclusion
Yes, Tedlar bags are very well-suited for VOC sampling in most standard applications. They combine chemical resistance with low permeability and ease of use. However, for critical compounds or long-term storage, we recommend evaluating the application-specific requirements.
We offer a wide range of Tedlar bags (as well as various other gas sampling bags such a multi-foil bags, Kynar bags and Teflon bags) in different volumes and with various fittings (PP, PTFE, stainless steel), suitable for air sampling. Feel free to contact us at info@medi-sense.nl for advice or a custom quotation.
