How Sorbent Tube Sampling Works

Sorbent tube sampling is the NIOSH/OSHA approved method for collecting most hazardous gases and vapors from the air. Federal law has established permissible exposure limits (PELs) for workers' exposures to a variety of airborne chemical hazards. These limits are specified in several ways: eight-hour Time-Weighted Averages (TWAs), Short-Term Exposure Limits (STELs) and Ceiling values. Eight-hour TWA limits are specified for full-shift exposures. STELs are usually issued as 15 minute exposure limits and Ceiling values are issued as peak levels not to be exceeded at any time during the working day. Sorbent tubes have been established as a reliable tool for each of these sampling requirements.

As easy as A...B...C...

A... Collect sample with a sorbent tube. A sample is collected by opening a tube, connecting it to a sample pump, and pulling air through the tube with the pump. Airborne chemicals are trapped onto the surface of the sorbent. The tube is then sealed with push-on caps, and sent to a laboratory for analysis.

B...

Extract sample from sorbent.
Lab personnel remove the sorbent and extract the trapped chemical using solvents or heat.

C...

Analyze sample.
The sample extracted from the tube is analyzed to determine the amount of chemical hazard present. A single tube may provide enough sample to permit several analyses.

 

The worker is shown wearing a sorbent tube and a sample pump to determine her exposure to chemical hazards during the entire work shift.

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	Consult the method or the SKC Air Sampling Guide to determine the appropriate sorbent tube to use for the chemical being sampled.
	Just before sampling, use a scorer/breaker tool to uniformly break the ends of the sorbent tube to a 2 mm diameter or half the diameter of the tube body.
	Keep the tube in a vertical position during sampling to prevent the possibility of channeling that can lead to undersampling.
	The arrow on the tube indicates air flow direction and should point to the tube holder and pump. If no arrow is present, the smallest section should be near the tube holder.
	Ship the sample to a laboratory as soon as possible; avoid excessive heat and rough handling.

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SKC offers a complete family of sorbent tubes -

over 140 for testing many chemical hazards

 

Click on the link to go to the sorbent tube tables:

• SKC Sorbent Tubes Listed by Catalog Number

• SKC Sorbent Tubes Listed by Sorbent

• Sorbent Tube FAQs

 

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This page was last modified September 20, 2004