volatile organic compounds

EPA’s Method 21, entitled “Determination Of Volatile Organic Compound Leaks,” calls for a portable instrument to be used for this purpose, and details certain specifications and calibration requirements.

“Volatile Organic Compounds,” better known as VOC’s, have been defined by EPA to mean:

“[A]ny compound of carbon, excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates, and ammonium carbonate, which participates in atmospheric photochemical reactions.”

This definition is further qualified, per 40 CFR Part 51.100(s).

Here is additional information from EPA.


It is true that most Method 21 work is done using infrared, photoionization, or flame ionization detectors, since these techniques can handle a broad range of organic compounds. But, if you don’t need to measure a broad range of compounds, and if your requirements include ethyleneethylene oxide, formaldehyde, hydrogen cyanide, hydrogen peroxide, peracetic acid,  or propylene oxide, then our portable analyzers will more than do the trick. Bear in mind that in most cases, you should use the UL-Classified intrinsically safe version of the analyzer, and these are readily available.

Unlike photoionization or flame ionization units (if not equipped with chromatographic columns), Interscan gas analyzers are quite specific for the target compound, and often boast greater sensitivity, as well. Portable infrared analyzers offer excellent specificity, but are cumbersome and expensive, and often lack sufficient sensitivity.

Finally, Interscan analyzers are usually priced more attractively than alternative products.

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