Use for volatile organics such as vinyl chloride, benzene, methylene chloride, PCE, etc.
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Analysis
Analyzed by transferring a measured volume of air from the canister or bag to a cryogenic trap and hence to the GC/MS analytical system (preferred for legal defensibility).
Equipment
Canisters or bags plus one for QC, compensating critical orifice or small pump for integrated samples, flow controller/flow meter, pressure/vacuum gauge. Projects may also require onsite measurement of temperature, relative humidity, barometric pressure (absolute), wind direction and speed. Clients may also need heavy walled Teflon tubing, tees, connectors, etc.
Detection Limits
Detection limits – 0.2 ppbv
Advantages
Convenience, easy to ship, low detection limits, applicable to broad range of target compounds. Can run duplicates and/or MS/MSD with certified reference standard rather than client sample. Sampler does not need to estimates how much air to sample.
Disadvantages
Canister supply may be taxed by very large projects. Some polar compounds may have an affinity for canister walls at low concentrations. Bags can contaminate the sample with chlorinated compounds.
Alternatives
TO-1 & TO-2 separately or combined, TO-3, some NIOSH methods
Ambient air surveys, fence line monitoring, impacted neighborhoods, some odor problems, indoor air, risk assessment, sulfur gases (bag sampling required), TPH in air, etc. |