space vapors in the vials periodically using poly-
LITERATURE CITED
acrylate SPME fibers after periods ranging from 6
to 173 days and quantified the signatures using
ASTM (1999) Standard specification for standard
GC-ECD and a non-equilibrium calibration pro-
sand. C 778-990. West Conshohocken, Pennsylva-
cedure.
nia: American Socirty for Testing and Materials.
Qualitatively, the isomers of DNB, DNT, and
EPA (1995) SW 846 Method 8330. U.S. Environ-
TNT account for all of the vapors detected in the
mental Protection Agency, Washington, D.C.
headspace above these soils. In general, 2,4-DNT,
Grant, C.L., T.F. Jenkins, and S.M. Golden (1993)
1,3-DNB, and 2,4,6-TNT were the target analytes
Experimental assessment of analytical holding
present at the highest concentrations in the head-
times for nitro-aromatic and nitramine explosives
space vapor above all three soils maintained at
in soil. USA Cold Regions research and Engineer-
23C. At 4C, vapor concentrations were reduced
ing Laboratory, Special Report 93-11.
by at least a factor of ten; the reduction was great-
Howard, P.H. and W .M. Meylan, Ed. (1997)
est for 2,4,6-TNT, the signature chemical with the
Handbook of Physical Properties of Organic Chemi-
lowest vapor pressure. At 12C, vapor concen-
cals. Boca Raton: CRC Press.
trations were further reduced; reductions were
Jenkins, T.F., D.C. Leggett, and R.P. Murrmann
greater for 2,4-DNT and 2,4,6-TNT, compared
(1974) Preliminary investigation of the perme-
with the more volatile 1,3-DNB.
ability of moist soils to explosive vapor. In
Concentrations were generally greater above
Appendix B of G. Spangler (1974) Physical model
sands than above silty soils, and greater above
for the subterranean movement of explosive
silts than clay. Soil moisture level was also an
vapors from mines. Fort Belvoir, Virginia: U.S.
important variable in controlling headspace
Army Mobility Equipment Research and Devel-
vapor concentrations. For air-dried soils, vapor
opment Center Report 2095.
concentrations were lower than for either of the
Leggett, D.C., T.F. Jenkins, and R.P. Murrmann
higher moisture contents for all three soils at all
(1977) Composition of vapors evolved from mili-
temperatures where vapors could be detected.
tary TNT as influenced by temperature, solid
Measurable concentrations of 2,4,6-TNT, 2,4-
composition, age, and source. USA Cold Regions
DNT, and 1,3-DNB were obtained in the top 5
Research and Engineering Laboratory, Special
mm of sand and silt held at all three tempera-
Report 77-16.
tures. Lower concentrations of these chemicals
were detected in the clay at 23C, but concentra-
of solid phase microextraction for air analyses
tions were generally below detection limits at
based on physical chemical properties of the coat-
lower temperatures.
ing. Analytical Chemistry 69: 206215.
Soilair partition coefficients were computed
Maskarinec, M.P., C.K. Bayne, L.H. Johnson,
for samples that had detectable signatures in both
S.K. Holladay, R.A. Jenkins, and B.A. Tompkins
the headspace and the surface soil. These parti-
(1991) Stability of explosives in environmental
tion coefficients are higher for 2,4,6-TNT than for
water and soil samples. Oak Ridge National Lab-
2,4-DNT or 1,3-DNB, they decrease as tempera-
oratory Report ORNL/TM-11770.
ture increases, they are highest for clay and low-
Murrmann, R.P., T.F. Jenkins, and D.C. Leggett
est for sand, and they are higher for air-dry than
(1971) Composition and mass spectra of impuri-
moist soil. At equilibrium, 1 mL of headspace
ties in military-grade TNT vapor. USA Cold Re-
vapor contains only one thousandth to less than
gions Research and Engineering Laboratory, Spe-
one millionth the mass of signature present as
cial Report 158.
does 1 g of the associated soil. Thus, it may be
Pella, P.A. (1977) Measurement of the vapor pres-
possible to use the natural preconcentration of
sures of TNT, 2,4-DNT, 2,6-DNT, and EGDN.
signature vapors that takes place on surface soil
Journal of Chemical Thermodynamics, 9: 301305.
to increase their detectability.
Zhang, Z. and J. Pawliszyn (1993) Headspace
solid-phase microextraction. Analytical Chemistry,
65: 18431852.
21
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