ODOUR AND GAS SAMPLING
The bag you pick decides how much of your sample is still there when it reaches the lab. Scentroid makes air and gas sampling bags in four materials, in sizes from 1 L to 60 L, with fittings to match your sampler.
Every bag is made in-house in Canada, pressure tested and ready to ship.
4
bag materials
1 L to 60 L
standard sizes plus custom
1000+
bag orders for large sampling programs
80+
countries we ship to
WHY IT MATTERS
Odour and VOC samples start to change the moment they go into a bag. Compounds stick to the bag walls, slowly pass through the film or mix with chemicals given off by the film itself. By the time a sample is analysed, some of what you collected can be gone. Peer reviewed studies have measured this and the gap between bag materials is large.
Sticky compounds like organic acids and phenols cling to the inside of the bag. A denser film and less surface area per litre keep more of them in the air.
Compounds and moisture can escape through the bag wall. Researchers found this is a main loss path in Nalophan and Tedlar bags, while PTFE losses were mostly limited to adsorption.
Some films give off chemicals of their own. One study found high background levels of DMAC and phenol coming from Tedlar bags, which can end up in your results.
OUR BAGS
Choose by what you are sampling and how long it will sit before analysis. Every bag comes with your choice of fitting and can be made to a custom size.
Our most popular bag for odour and VOC work. Dense pure PTFE film with zero background odour. Great for H2S, petrochemicals, humid samples and longer holding times. Reusable up to about 30 times.
The long standing industry standard. Made with DuPont Tedlar film and pre-purged with our heated purger for low background. A good fit for samples analysed within 6 to 12 hours.
An affordable single use bag for short term storage and on site analysis. Order pre-made bags or save on large campaigns with Nalophan rolls and DIY kits.
Electro-polished 316L stainless steel film with welded seams. Built for corrosive gases, very high H2S, benzene and GC-MS work where purity matters. A flexible alternative to SUMMA canisters.
A compact 12 x 17 cm PTFE bag for collecting breath samples in research and healthcare settings. Easy to clean and reuse.
Need a different size or fitting combination? We make every bag in-house, so custom sizes cost nothing extra and in most cases ship the same day.
REUSE YOUR BAGS
PTFE, Tedlar and stainless steel bags are made to be reused, and the SP20 does the cleaning for you. It switches between hot air and vacuum to pull odour molecules off the bag walls, cutting a typical one hour purge down to about 7 minutes. Set the temperature for the bag you are cleaning, 150 °C for PTFE or 200 °C for stainless steel, and let it run.
BAG SELECTION GUIDE
Use this as a quick guide. If you are not sure, send us the compounds you are sampling and how long the sample will sit before analysis and we will point you to the right bag.
| Bag | Best for | Analyse within | Reusable | Sizes |
|---|---|---|---|---|
| PTFE | High VOC and H2S, petrochemicals, humid samples and low odour thresholds | Up to 30 hours | Yes, up to about 30 uses | 1 L to 40 L and custom |
| Tedlar | Moderate to high VOC and H2S and general odour sampling | 6 to 12 hours | Yes | 1 L to 40 L and custom |
| Nalophan | Short term storage, on site analysis and budget sampling campaigns | Under 6 hours | No, single use | 5 L to 60 L, rolls and DIY kits |
| Stainless steel | Corrosive gases, very high H2S, benzene and GC-MS analysis | Longest holding time, similar to SUMMA canisters | Yes, no costly cleaning needed | 8 L (12 x 24 in) |
| PTFE breath bag | Breath samples for research and healthcare | Ask us about your application | Yes | 12 x 17 cm |
Sampling benzene or other petrochemicals? Skip Tedlar and Nalophan and use PTFE or stainless steel instead.
SAMPLE RECOVERY DATA
We compared how much odour sample stayed in each bag type after a day of storage, across eight real odour sources. PTFE held on to the most sample every time. The biggest gap was gas refinery samples, where Tedlar and Nalophan lost more than 80 percent.
Percent of sample recovered after 24 hours of storage. Scentroid test data by odour source.
INDEPENDENT RESEARCH
Universities in Denmark, China and Poland have tested how well different bags hold odour and VOC samples. The results point the same way.
AARHUS UNIVERSITY · 2018
Researchers tested Scentroid PTFE bags against Tedlar and Nalophan with key livestock odorants. Recovery ranked PTFE first, then Tedlar, then Nalophan. 4-methylphenol was almost completely lost in Nalophan and Tedlar bags. With gentle heating before analysis, a 5 L PTFE bag kept every odorant tested at 72 to 99 percent after 48 hours.
ZHEJIANG UNIVERSITY · 2020
A comparison of FEP, Tedlar, BOPET and Fluode bags for pig farm odours found that FEP, a fluoropolymer in the same family as PTFE, recovered the most after 24 hours. That was about 48 percent of the odour versus 24 percent for Tedlar. Tedlar bags also released background chemicals including DMAC and phenol.
WARSAW UNIVERSITY OF TECHNOLOGY · 2015
Gas mixtures were held in Tedlar bags for 78 hours and measured with a Scentroid SM100 olfactometer and a GC. Losses were small over the first 30 hours. By the end, benzene, acetone, vinyl chloride and several other compounds had dropped to zero.
The takeaway: pick the bag for your compounds and your timeline, and get samples to the lab as fast as you can.
Studies on sampling bag performance, including work done with Scentroid bags and instruments. Scroll for more.
Tested bags made by Scentroid. PTFE blanks had zero background odour. After 24 hours, a wastewater sample lost about 23 percent in PTFE, 35 percent in Tedlar and 60 percent in Nalophan.
Looks at how storage time, air freight conditions and humidity degrade samples, and how PTFE bags and on-site olfactometry reduce the loss.
Aarhus University study using Scentroid PTFE bags. Recovery ranked PTFE, then Tedlar, then Nalophan.
FEP fluoropolymer bags recovered the most odour after 24 hours. Tedlar released background chemicals.
78 hour storage test in Tedlar bags measured with a Scentroid SM100 olfactometer and GC.
How livestock odours and odorous compounds hold up over time in Tedlar (PVF) bags.
Recent work on Nalophan bags showing humidity has the biggest effect on losses, mainly for H2S and oxygenated compounds.
Our write-up of the Aarhus University study.
Plain language guides to each bag material.
Tedlar · Nalophan · Stainless steel · Sampling materialsWHO USES THEM
Odour audits at headworks, clarifiers and biosolids
Surface, flux chamber and perimeter sampling
Compliance testing and odour complaint investigations
Dynamic olfactometry and GC-MS analysis
VOC, benzene and H2S sampling
Barn, manure and feedlot odours
Emission and sample stability studies
Breath sample collection
Choose your
HOW TO ORDER
01
PTFE, Tedlar, Nalophan or stainless steel. Not sure which one? Use the guide above or ask us.
02
PTFE and Tedlar come in 1 L, 3 L, 5 L, 10 L, 25 L and 40 L. Nalophan comes in 5 L to 60 L bags or rolls from 100 m to 1000 m.
03
2-in-1 polypropylene, 2-in-1 PTFE, PTFE coated nylon or stainless steel to match your sampler and tubing.
04
Stocked sizes ship right away. Custom bags are made in-house and in most cases ship the same day.
Every Scentroid bag is made in a dedicated clean room with continuous HEPA and carbon filtration.
Every bag is pressure tested to 10 inches of water before it ships, so seals stay tight in the field and in transit.
BULK AND PROJECT ORDERS
Running a large sampling program or stocking a lab for the year? We make our bags in-house in Canada, so we can produce runs of 1000+ bags in the sizes and fittings you need and schedule deliveries around your project. Send us your quantities and timeline and we will put together a quote.
CLEAN, REUSE AND SAMPLE
PTFE, Tedlar and stainless steel bags can be cleaned and used again, which brings your cost per sample way down. Pair them with the right purger and sampler for a complete setup.
Cycles hot air and vacuum to clean a bag in about 7 minutes instead of the usual hour. Labs use it to reuse PTFE bags up to about 30 times.
Uses ozone to disinfect and decontaminate sample bags, PTFE lines and probes, with a built-in carbon filter for safe operation.
Fill bags without pulling the sample through a pump, so nothing contaminates it on the way in. Works with all our bag types.
RESOURCES
See our bags in action and take the full product guide with you.
Every bag, size and fitting in one PDF, plus our recovery data and an ordering guide you can share with your team.
A walk through our Nalophan, Tedlar, PTFE and stainless steel bags and when to use each one.
A closer look at what makes our newer bag materials different.
FAQ
For most odour work PTFE is the best all round choice. It has zero background odour, holds samples longer than Tedlar or Nalophan and can be reused. For very corrosive gases or GC-MS work, stainless steel is the safest choice. Nalophan works well when samples are analysed within a few hours.
It depends on the bag and the compounds. As a guide, analyse Nalophan samples within 6 hours, Tedlar within 6 to 12 hours and PTFE within 30 hours. The EN 13725 odour standard allows up to 30 hours between sampling and analysis. Stainless steel bags give the longest holding time of any bag we make.
Both are fluoropolymer films. PTFE film is much denser than Tedlar, so less of the sample is lost through the bag wall, and it has no background odour. Independent testing has shown better recovery in PTFE bags for many odorants. Tedlar is a proven option with a long track record for shorter holding times.
Yes. PTFE, Tedlar and stainless steel bags can be reused after cleaning. With the SP20 Heated Air Purger, labs routinely reuse PTFE bags up to about 30 times. Nalophan bags are made for single use.
Use PTFE or stainless steel. Stainless steel is the best choice for very high H2S. We do not recommend Tedlar or Nalophan for benzene and other petrochemicals.
Yes. All our bags are made in-house in Canada, so we can build custom sizes and fitting combinations at no extra charge. In most cases custom bags ship the same day.
Yes. We supply sampling programs, consultants and labs with orders of 1000+ bags. Contact us with your sizes, fittings and delivery dates and we will send a quote.
Yes. Scentroid ships to more than 80 countries and works with local distributors for support.