Table 4. Available on-site analytical methods for explosives
in soil.
Analyte(s)
Test type
Developer/test kit
A. Nitroaromatics
Colorimetric
CRREL,* Ensys RISc
1. TNT
Colorimetric
CRREL, Ensys RISc
USACE†
Colorimetric
Colorimetric
ENVIROL
Immunoassay
DTECH
Idetek Quantix
Ohmicron RaPID Assay
EnviroGard
2. TNB
Colorimetric
CRREL, EnSys RISc
Immunoassay
Ohmicron RaPID Assay
3. DNT
Colorimetric
CRREL, EnSys RISc
4. Tetryl
Colorimetric
CRREL
B. Nitramines
Colorimetric
CRREL, EnSys RISc
1 . RDX
Colorimetric
CRREL, EnSys RISc
Immunoassay
DTECH
2. HMX
Colorimetric
CRREL, EnSys RISc
3. NQ
Colorimetric
CRREL
C. Nitrate esters
Colorimetric
CRREL
1. NC
Colorimetric
CRREL
2. NG
Colorimetric
CRREL
3. PETN
Colorimetric
CRREL
D. AP/PA
Colorimetric
CRREL
*U.S. Army Cold Regions Research and Engineering Laboratory.
†U.S. Army Corps of Engineers, Kansas City District.
EnSys RISc, is used to determine TNT and RDX in
trophotometer. The TNT concentration is calcu-
soil. EnSys RISc is the commercial version of the
lated by comparing results to a control sample. The
CRREL method for TNT and RDX. In addition to
U.S. Army Corps of Engineers (USACE) and
the CRREL method, USACE and ENVIROL devel-
ENVIROL procedures use methanol for extraction,
oped colorimetric methods for TNT. EnSys RISc
and the ENVIROL procedure uses solid phase ex-
and CRREL have additional colorimetric methods
traction and liquidliquid transfer, prior to reac-
that can also be used to determine nitramines
tion with base and formation of a colored anion.
(HMX and NQ), nitrate esters (NC, NG, and
The RDX test has more steps.
PETN), and AP/PA. ENVIROL is developing an
The various immunoassay methods differ con-
RDX colorimetric method that should be available
siderably in their steps; the DTECH method for
in spring 1998.
TNT is the simplest. In the DTECH kit, antibodies
specific for TNT and closely related compounds
Two companies, Idetek, Inc., and Strategic Di-
agnostics, Inc., manufacture commercial enzyme
are linked to solid particles. The TNT molecules
linked immunosorbent assay (ELISA) kits to de-
in the soil extract are captured by the solid par-
tect TNT in soil. Idetek, Inc., produces the Quantix
ticles and collected on the membrane of a cup as-
kit (both a plate and tube method are available),
sembly. A color-developing solution is added to
and Strategic Diagnostics, Inc., offers DTECH,
the cup assembly and the presence (or absence) of
EnviroGard, and Ohmicron RaPID Assay. DTECH
TNT is determined by comparing the solution in
kits are also available for RDX. Other explosives
the assembly cup to a color card or by using the
compounds can sometimes be detected using im-
simple field test meter. The color is inversely pro-
munoassay kits because of their cross reactivity
portional to the concentration of TNT.
(see Interferences and Cross Reactivity section).
The EnviroGard TNT immunoassay kit was for-
Method type, analytes,
merly produced by Millipore Corp.
and EPA method number
The first criteria column in Table 3 lists the type
of soil screening method, the analytes it detects,
Detection limits and range
The lower detection limits of most methods are
and the EPA SW-846 draft or proposed method
near or below 1 ppm. The detection range of a test
number. A commercially available colorimetric kit,
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