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AGAT partners with SiREM to provide the Waterloo Membrane Sampler™ for passive soil vapour sampling

AGAT Laboratories in partnership with SiREM, recently announced that the Waterloo Membrane Sampler™ (WMS) is now available for passive soil vapour sampling exclusively at AGAT.

The Waterloo Membrane Sampler™ (WMS) is a cost-effective, simple-to-use passive sampler for soil vapour. The WMS provides quantitative concentration measurements with similar accuracy and precision to conventional active soil vapour samples collected using Summa canisters or TD Tubes.

The WMS is a permeation-type passive sampler. When it is exposed, the VOCs permeate through the membrane covering the top of the sampler vial, driven by a concentration gradient. The sorbent inside the sampler then traps the vapours and then the mass of each compound is determined by GC/MS at AGAT Laboratories.

Frequently Asked Questions

How does the WMS work?
Passive samplers can be classified into two general types based on how the VOC uptake is controlled: (1) those that rely on diffusion through a stagnant air region (passive diffusion samplers) and; (2) those that rely on permeation through a nonporous membrane (passive permeation samplers). In the latter, VOCs permeate through the uptake-rate limiting membrane before they are collected by the sorbent. The Waterloo Membrane Sampler™ is a permeation-type passive sampler. When it is exposed to air, VOCs in the air permeate through the membrane covering the top of the sampler vial, driven by a concentration gradient. The sorbent inside the sampler then traps the vapours.
Is the WMS impacted by environmental changes?
Unlike other media, the WMS has minimal effect from moisture, wind velocity, or barometric pressure. The hydrophobic nature of the membrane excludes water and also prevents turbulent uptake so the sampler can be deployed in high velocity environments such as soil gas extraction systems.
How long does the WMS have to be deployed?
 The WMS can be deployed for a minimum of a few days to up to 30 days. You can calculate deployment times by using the online Sample Duration Calculator to determine what WMS will work best for your site.
Why are there different types of WMS samplers?
Each WMS is designed to work in different types of soil as follows:
  • The WMS-LUTM is a low-uptake WMS used for vapour concentrations in soil gas. The lower uptake rates mitigate the effect of the sampler starvation that may occur when collecting soil gas, and will allow for quantitative soil gas sampling in drier subsurface conditions.
  • The WMS-TMTM is designed for VOC vapour concentrations in soil gas with low permeability or very wet soils.
What is the hold time for the WMS?
Once a sample has been taken, the hold time is 14 days.  Samplers should be kept cool (ice packs but NO ICE is recommend, for these types of samples should not get wet) and shipped back to the lab. Target temperature is 10°C.

 Is the use of the WMS accepted by the Regulator?
It depends on the jurisdiction.  In Ontario, Under “Regulation 153 Vapour Intrusion Guidelines,” the WMS is accepted as alternative sampling media for the collection of soil and sub-slab vapour. There is no prescribed sampling method that is recommended or preferred over another. It is the responsibility of the QP to determine what sampling media would be best for their site.

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