US Geological Survey
The Reston Chlorofluorocarbon Laboratory
Low-Level VOCs FAQ
- What do you mean by the term "low-level" VOC?
The term "low-level" refers to concentrations that typically are below the minimum detection level (MDL) for VOCs determined by purge and trap capillary column gas chromatography with mass spectrometry (GC-MS), and can be at concentrations as low as 2 to more than 4 orders of magnitude below the commonly reported GC-MS MDL of 0.01 to 0.2 ug/L.
- What VOCs are detected?
The electron-capture detector detects halogenated VOCs. Approximately 63 halogenated VOCs have been detected in chromatographs of untreated ground water; 25 of these compounds have been identified (see Table 1 below).
- How are low-level VOC samples collected?
Same as for CFC samples.