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Dense Nonaqueous Phase Liquids (DNAPLs)

Detection and Site Characterization

Halogenated Alkanes

Trichlorofluoromethane

Trichlorofluoromethane (TCFM) is a volatile chlorinated organic and as such is subject to most standard characterization and analytical techniques used on this class of chemicals. Methods such as vertical profiling, membrane interface probe, and standard GC/MS are discussed in the main section for DNAPLs detection and site characterization.

Diffusion Samplers

While Diffusion Samplers have been used mostly for chlorinated ethenes and BTEX, they have been found to work for TCFM (ITRC 2004).

Laboratory Methods

Analysis of TCFM can be performed using standard analyses such as SW-846 methods 8021b, 8260b, 8260c, and 8261a

Field Screening Methods

Given its Henry's Constant, TCFM should be detectable using headspace analysis with a field GC. Standards should be run to verify detection limit requirements. The photoionization energy for TCFM is 11.77 eV (EPA 1994); hence, a PID detector is not likely to detect it.

Gastec Corporation produces a detector tube system for fluorochlorocarbons. The system is not specific to an individual chlorofluorocarbon and has detection limits starting at one ppm. The tubes can be used for ambient air sampling or for headspace analysis.

References

Standard Operating Procedure # 2114: Photoionization Detector HNU
U.S. EPA, Emergency Response Team, 16 pp, 1994

This document contains an extensive list of chemicals with their photoionization potentials.

Technical and Regulatory Guidance for Using Polyethylene Diffusion Bag Samplers to Monitor Volatile Organic Compounds in Groundwater
Interstate Technology & Regulatory Council (ITRC). DSP-3, 78 pp, 2004