An Investigation of Different Types of Storage Containers for Method 325

Oral Presentation

Prepared by J. Brown, O. Shimelis, M. Halpenny
Supelco, 595 North Harrison Rd, Bellefonte, PA, 16823, United States

Contact Information:; 814-359-5917


The new EPA Method 325 uses Thermal Desorption (TD) tubes to passively collect air samples along the fence line of petroleum refineries. The laboratory is to ship the pre-conditioned TD tubes to the testing site sealed (with long-term metal storage caps at both ends) and placed inside some sort of shipping/storage container. In the field, the TD tubes are removed from the storage container and the long-term storage cap from the sampling inlet is replaced with a diffusive sampling cap. With the diffusive sampling caps in place, the TD tubes are placed in a weather-proof shelter along the perimeter of the property, and they remain there for 14-days to capture the average concentration of VOCs emitted from the refinery. After sampling, the diffusive sampling cap is replaced with the original long-term storage cap, and the tube is placed back into the storage container to be shipped to the laboratory for analysis. The implied purpose of the storage container is to provide additional protection from VOCs during transport. The method states that the storage containers are to be made of glass, metal or rigid non-emitting polymer.

It is well-known that not all materials provide the same barrier against VOCs. This research evaluates the use of different storage containers made of different materials. We investigate what VOCs background is emitted by these containers, and how effective they are at preventing the ingress of the VOCs from external sources.