in Figure 6. Clearly there is a vast decrease in in-
of Drinking Water. Washington, D.C.: U.S. Envi-
ronmental Protection Agency.
terferences released from the two solid phases.
There remains, however, a small interference peak
EPA (1988a) Health Advisory for RDX. Criteria and
at the retention time for RDX in the two chromato-
Standards Division, Office of Drinking Water.
grams for the SPE methods that is not observed
Washington, D.C.: U.S. Environmental Protection
for the SOE (Fig. 6) and does not confirm as RDX
Agency.
using the LC-CN confirmation column (Fig. 7).
EPA (1988b) Health Advisory for HMX. Criteria and
This peak was observed in the LC-18 chromato-
Standards Division, Office of Drinking Water.
grams for both SPE-C and SPE-M for the same six
Washington, D.C.: U.S. Environmental Protection
well waters that resulted in release of interferences
Agency.
in the original study. Observation of these peaks
EPA (1988c) Health Advisory for 1,3-Dinitrobenzene.
would require that a confirmation analysis be con-
Criteria and Standards Division, Office of Drink-
ducted and would result in quantitative RDX es-
ing Water. Washington, D.C.: U.S. Environmental
timates ranging from 0.2 to 0.6 g/L if careful
Protection Agency.
scrutiny of an LC-CN confirmation analysis had
EPA (1992a) Nitroaromatics and Nitramines by HPLC.
not been done. Thus, when SPE preconcentration
Second Update SW846 Method 8330. Washington,
is used, the detection limit for RDX should be
D.C.: U.S. Environmental Protection Agency.
raised to about 0.6 g/L to eliminate the chance
EPA (1992b) Dinitrotoluene Health Advisory. Crite-
ria and Standards Division, Office of Drinking
for misidentification due to this small interference
Water. Washington, D.C.: U.S. Environmental Pro-
peak.
tection Agency.
Etnier, E.L. (1987) Water quality criteria for 2,4-dini-
CONCLUSIONS AND RECOMMENDATIONS
trotoluene and 2,6-dinitrotoluene. AD-ORNL6312.
Oak Ridge National Laboratory Report, Oak Ridge,
Solid-phase extraction, in both the cartridge
(SPE-C) and membrane (SPE-M) formats, was
Tennessee.
evaluated for the ability to preconcentrate nitroar-
Jenkins, T.F., P.H. Miyares, K.F. Myers, E.F. McCor-
omatics, nitramines, and aminodinitroaromatics
mick and A.B. Strong (1994a) Comparison of solid-
from water samples prior to analysis by RP-HPLC
phase extraction with salting-out solvent extraction
(SW846 Method 8330). A series of 33 groundwa-
for preconcentration of nitroaromatic and nitramine
ter samples from the Naval Surface Warfare Cen-
explosives from water. Analytica Chimica Acta, 289:
ter was used for comparison. New, manufacturer-
6978.
cleaned solid-phase materials (Porapak RDX for
Jenkins, T.F., P.G. Thorne and M.E. Walsh (1994b)
SPE-C and SDB-RPS for SPE-M) were compared
Fieldscreening method for TNT and RDX in
to salting-out solvent extraction with respect to
their recovery of target analytes and their produc-
Engineering Laboratory, Special Report 94-18.
tion of chromatographic interferences.
Jenkins, T.F., P.H. Miyares, K.F. Myers, E.F. McCor-
Based on these results, we recommend that
mick and A.B. Strong (1992) Comparison of car-
solid-phase extraction, in either the cartridge or
tridge and membrane solid-phase extraction with
membrane format, be included as an option along
salting-out solvent extraction for preconcentration
with salting-out solvent extraction for the precon-
of nitroaromatic and nitramine explosives from
water. USA Cold Regions Research and Engineer-
centration step in SW846 Method 8330. Compar-
ing Laboratory, Special Report 92-25.
ison of the results of this study and earlier work
Kayser, E.G. and N.E. Burlinson (1982) Migration
(Jenkins et al. 1992, 1994) demonstrates the ne-
cessity of using carefully cleaned solid phases for
of explosives in soil. Naval Surface Weapons Cen-
this purpose, or interferences will be released for
ter Report TR 82566.
certain water matrices.
LeBrun, G., P. Rethwill and J. Matteson (1993) De-
termination of explosives in surface and ground-
water. Environmental Laboratory, p. 1215.
LITERATURE CITED
Miyares, P.H. and T.F. Jenkins (1990) Salting-out
Bouvier, E.S.P. and S.A. Oehrle (1995) Analysis and
solvent extraction method for determining low lev-
identification of nitroaromatic and nitramine ex-
els of nitroaromatics and nitramines in water. USA
Cold Regions Research and Engineering Labora-
array detection. LC-GC, 13(2): 120130.
tory, Special Report 9030.
EPA (1989) Trinitrotoluene Health Advisory. Office
Miyares, P.H. and T.F. Jenkins (1991) Improved salt-
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