Sponsored by Assay Technology

Occasionally, a thoughtful, careful customer will ask us about the capacity of the organic vapor badges (546, 566, and 525). They know if the capacity of the sampling media is exceeded, they will get a low-biased result. So, they ask:

• Why don’t Assay badges have a back-up carbon wafer for high-capacity sampling?
• How do you know you've exceeded the capacity of the monitor?
  

Usually, customers are comparing Assay Technology badges against the 3M 3520, which has a second wafer, or a charcoal tube, which has a back section. In both cases, when the capacity of the front section is reached, the chemical will start to be collected on the back section, indicating that the capacity of the media was exceeded.

Since Assay Technology badges do not have a back section, there is no indicator that the capacity of the badge was reached. But before you reach for media that have a back section, consider that the Assay 546 badge has been designed so you would have to have concentrations many times over the PEL before the capacity is exceeded, even for chemicals with high PELs like toluene and ethanol. This eliminates the need for an additional section.

Read the rest of this post on the Assay Technology website​.