Effectiveness of purge-and-trap for measurement of volatile organic compounds in aged soils

Journal Article · Tue Oct 01 04:00:00 EDT 1996 · Analytical Chemistry (Washington)

DOI:https://doi.org/10.1021/ac960009c· OSTI ID:420792

Askari, M D.F. ^[1]; Maskarinec, M P; Smith, S M; Travis, C C ^[2]; Beam, P M ^[3]

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1. Univ. of Tennessee, Knoxville, TN (United States)
2. Oak Ridge National Lab., TN (United States)
3. U.S. Department of Energy, Washington, DC (United States)

The U.S. EPA-recommended method for measurement of trace levels of volatile organic compounds (VOCs) in soil, purge-and-trap, measures the readily desorbable organic contaminants from soil pore spaces and external soil surfaces. It does not, however, measure contamination that has diffused into internal micropores of soil matrix. Thus, the purge-and-trap method measures only a small fraction of total soil contaminants, especially in long-contaminated soils, where nearly 90-99% of contamination may be in the interior of the soil matrix. We compared three methods for determination of VOCs in aged field samples: purge-and-trap, methanol immersion, and hot solvent extraction. Hot solvent extraction proved to be much more effective than the U.S. EPA-approved purge-and-trap technique. For three long-contaminated soils containing such VOCs as trichloroethene, benzene, toluene, chloroform, methylene chloride, and cis-1,1-dichloroethylene, recovery from purge-and-trap ranged between 1.5 and 41.3% that of hot solvent extraction. Our data show that purge-and-trap may not be the best methodology for measuring soil VOCs concentrations, particularly in aged soils. It is clear from this and previous studies that the best overall choice for soil VOCs measurements is hot solvent extraction. These results also indicate the inefficiency of purge-and-trap as a method for evaluating vapor extraction remediation technology. 25 refs., 2 tabs.

• DOE Contract Number: AC05-96OR22464
• OSTI ID: 420792
• Journal Information: Analytical Chemistry (Washington), Journal Name: Analytical Chemistry (Washington) Journal Issue: 19 Vol. 68; ISSN ANCHAM; ISSN 0003-2700
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
54 ENVIRONMENTAL SCIENCES
58 GEOSCIENCES
CHEMICAL ANALYSIS
MEASURING METHODS
METHANOL
ORGANIC COMPOUNDS
SOILS
SOLVENT EXTRACTION
US EPA