Industrial hygienists have always wanted to sample for a wide variety of volatile organic compounds (VOCs) on a single charcoal tube or passive monitor using a single, effective extraction method. Now they can!

 

NIOSH and OSHA methods using a single component solvent are somewhat limited in that analytes such as butanol and hexane cannot be sampled and analyzed on the same sample matrix due to their distinct chemical properties (specifically polarity). Clients in the past have had to either submit multiple sampling media, or use the same media for both contaminants, and settle for poor recoveries of the polar compounds. In many cases, this meant workers would have to wear two or three sampling pumps or complex splitters in order to collect the additional samples needed for each sampling event.

 

Having large numbers of analytical methods also makes it difficult for clients to determine which analytes are compatible without using complicated compatibility tables.

 

Now, using our new universal solvent, clients can sample for more than 130 VOCs on the same sample media. Our labouratory can analyze the samples using a single analytical method with acceptable recoveries for all of these analytes, and the list is growing. Cheque out our website for the current list of compounds validated on the new method. If you don’t see a compound you need, give us a call and we’ll see if we can add it.

 

In addition to the universal solvent extraction, VOCs are now analyzed using dual gas chromatography (GC) capillary columns. The GC is configured with a non-polar and a polar column. The injected sample is simultaneously split on to the two GC columns using a 3-way fused silica splitter. Each column separates the analytes based on their chemical properties, specifically polarity (affinity and interaction with the stationary phase) and boiling points. Thus, each sample is confirmed by two different analytical methods. The use of both methods increases the confidence that each analyte is being correctly identified and quantified. An added advantage of using dual column gas chromatography, is analytes coeluting on one of the columns are typically resolved on the adjacent column.

 

The chromatogram below shows an example of this problem. Two compounds at 6.67 minutes have almost the same retention time. Situations like this make quantitation and identification difficult.

 

The chromatogram from the second column shows the same two compounds (retention times 8.78 and 9.10 minutes) with base line separation. Using the second column, both compounds can be identified and quantified with greater confidence.

Using the new SGS Galson modified NIOSH 1500/OSHA 7 method, you get: