Air Sampling Guide Help

Bureau Veritas' Air Sampling Guide is a quick reference for media and flow rates. Analytes can be searched either by chemical name or Chemical Abstract System number (CASN). Symbols or numbers indicating isomers or structures are given after the chemical name; for example, N-methyl-2-Pyrrolidone is listed as methyl-2-Pyrrolidone (N). An asterisk is used as a wild card for the chemical name. The CAS# must be entered as an exact match, including appropriate hyphenation (-).

If you do not find a particular compound by either chemical name or CASN, please e-mail us with your request and we will search to see if an appropriate method exists.

The air sampling guide is meant as a reference to follow when sampling for chemical contaminants that may be found in a workplace environment. The guidelines closely parallel the recommendations of OSHA or NIOSH. If the air sampling guide is used for other types of sampling such as indoor air quality, ambient air monitoring or short-term sampling, the flow rates and maximum air volumes may have to be modified. Please call the laboratory to discuss your specific sampling criteria.

Analyte Search:

For example, if you wish to search for Benzene, type either Benzene or Benz* in the analyte section. A list of 17 different analytes — ranging from Benzene, Benzene (STEL), Ethyl Benzene, Benzene Solubles or the Trimethyl Benzene isomers — will be returned to you. Simply click on the compound of interest and you will have a screen showing you the summary of the sampling method. This summary includes:

• Media
• Method
• Flow Rate
• CAS#
• Minimum Volume
• Maximum Volume

CAS Number Search:

Enter the appropriate CAS number, for example 111-76-2 in the CAS Number field and hit the search button. Four chemical names are displayed:

1. Butoxyethanol (2)
2. Butyl Cellosolve
3. Ethylene Glycol Monobutyl Ether
4. CAS#
5. Polysolve EB

These are all chemical synonyms for the same chemical compound. Click on the compound of interest to view a screen with the summary of the sampling method.

Flow Rates and Volumes are meant as guidelines. Short-term sampling can normally be done at faster flow rates. However, this depends on several factors including concentration, length of time, volatility of analyte and media.

Analytes taken on media that requires derivitization such as isocyanate sampling; formaldehyde, etc. have been validated for very specific sampling rates. There must be sufficient contact time between the analyte and the derivative to form the complex.

Where possible, Bureau Veritas uses large bed solid sorbent tubes to allow for maximum flexibility. All charcoal tubes provided by the lab are 600-mg tubes (400-mg front section and 200 mg back section). Solid sorbent tubes are normally designed to have a 2:1 ratio in the front to back section. This is designed to verify validity of results. Samples containing more than 25 percent of the analyte in the back section are considered by OSHA to be invalid samples. Please note that most reference to charcoal tubes in the media section have a media code of CT2. This notation reflects the new type of charcoal type material that is being supplied by all major distributors. Many of the chemical compounds show enhanced desorption efficiencies using the new media.

Some analytes may show two different types of media such as CT2/OR90. This type of notation indicates that we have evaluated the material on both types of media. You may need to check with the laboratory for compatibility of compounds.

* -- Next to any media indicates that analyte should be taken separately because of special digestion or extraction requirements. Although some compounds, such as the cellosolves, are desorbed in similar solvents, it is best to check with the laboratory for compatibility.

Other solid sorbents, such as OR90 or silica gel, may use the same tube, but again, require different desorbing agents or analysis. An example of this would be a silica gel tube, which can be used for either methanol or phenol. The tube would be desorbed in water to analyze for methanol, but desorbed in acetone for Phenol analysis.

** -- The bulk of the material must be submitted under separate cover. Samples are analyzed using the bulk material as a standard.

The Bureau Veritas laboratory will provide you with the appropriate sampling media. Please call the lab at (888)-576-7522, e-mail us or use the media order form.

Please note that every effort has been made to assure the accuracy of the air sampling guide. Notify the Bureau Veritas laboratory if you find any errors.