SiREM is pleased to announce the availability of a new passive sampler, the Waterloo Membrane Sampler™ (WMS™) for monitoring VOC vapor concentrations. Originally developed at the University of Waterloo, this sampler has undergone three years of applied research and is now available for commercial use.

The design incorporates a polydimethylsiloxane (PDMS) membrane across the face of a vial filled with a sorbent medium. VOC vapors partition into and permeate through the membrane. The sorbent then traps the vapors, and the mass of each compound is determined by GC/ MS. The uptake rate has been experimentally measured for many common VOCs and can easily be calculated for other compounds because it is directly proportional to the retention index, a property that is readily available in the scientific literature. Thus, you can use the WMS™ sampler to measure time-weighted average concentrations for virtually any VOC.

Advantages compared to conventional air sampling methods

  • Lower cost
  • Simpler sampling protocols
  • Lower reporting limits without a premium price
  • Longer time-integrated samples
  • Very small size (discrete to deploy, and easy to ship)

Benefits compared to other quantitative passive air samplers

  • Predictable uptake rates for less common compounds
  • Ability to measure Total Petroleum Hydrocarbons/Gasoline Range Organics
  • Minimal effect of moisture (good for subsurface monitoring)
  • Insensitive to wind velocity (good for outdoor and vent-pipe monitoring)
  • Ability to modify uptake rate to avoid starvation effect
  • Small diameter (easy to put in vent-pipes or sub-slab probes)
  • Competitive pricing

The WMS™ sampler is available through SiREM and analytical services are provided by Air Toxics Ltd. (Folsom, CA), a specialty air laboratory.

pdf The Waterloo Membrane Sampler for Indoor Air, Outdoor Air, Vent-pipes and Personal Air Monitoring

pdf The Low-Uptake WMS Sampler for Quantitative Passive Soil Vapor Concentration Measurement