dynamic nature of this system. The ADNT and
Table 5. Recovery of transformation products
DANT transformation products of TNT are
from compost using 100% or 50% H2SO4 after
formed, conjugate, and further bind as
base hydrolysis.
biotreatment of these soils takes place. Target
analytes spiked into these matrices are unstable
Concentration (mg/kg)
and recoveries are hence problematic.
4ADNT
2ADNT
2,6DANT 2,4DANT
None of the untransformed explosives TNT,
RDX, and HMX were detected in the hydrolysis
100% acid
63.1
5.1
4.5
75.1
spike recovery tests because of their instability in
basic solution. Results (Table 6) showed that the
50% acid
19.8
<0.1
3.1
97.1
procedure recovered from 73% to 90% of the
ADNTs and from 88% to 93% of the DANTs when
no solids were present. However, in the presence
of the TNT and diaminonitrotoluenes rose to
of compost, no ADNTs were detected and the re-
greater than 69%, while the recoveries of the
coveries of the DANTs dropped to 18%62%. In
aminodinitrotoluenes were less than 82%. The dif-
the presence of sand, the recovery of the ADNTs
ranged from 5 to 9% while the recovery of the
ficulty in recovering ADNTs, even in acidified
DANTs was from 9% to 40%. For all mixtures that
water matrices, has been reported previously
contained solids, the recovery of the 3,5-DNA sur-
(Jenkins et al. 1995).
rogate that was added to the neutralized hydroly-
It was apparent (Table 4) that the pH must be
sates immediately before solid-phase extraction
carefully controlled. A pH of 5.0 is recommended
ranged from 72 to 88%.
to provide a compromise between absolute recov-
The ability to hydrolyze and recover unbound
ery of all analytes and a reasonable recovery of
transformation products from composts changes
the 3,5-DNA surrogate so that solid-phase extrac-
over the time course of the treatment. Hydrolysis
tion recoveries can be estimated independently of
of the aerated composts released the greatest quan-
the hydrolysis/neutralization losses.
tities of TNT transformation products during the
Acid hydrolysis from addition of cold 50% acid
midpoint of the composting process (Table 2).
resulted in lower recoveries of TNT transforma-
Hydrolysis of the Day-40 compost released fewer
tion products than were recovered when 100%
sulfuric acid was used (Table 5). Nevertheless, we
transformation products, presumably because of
recommend the use of 50% acid because of the
further conjugation with formation of functional
potential for injury caused by spattering of hot acid
groups that are more resistant to hydrolysis. The
when 100% acid is used. It is important when as-
incomplete recoveries of TNT and transformation
sessing these analytical recoveries to realize the
products that were spiked to composts from the
Table 6. Percent recoveries from base/acid hydrolyzed solution
(no solid), compost, and sand. No TNT, RDX, or HMX were re-
covered.
% recovery of spikes
4ADNT
2ADNT
2,6DANT
2,4DANT
3,5DNA
Solution
90
73
88
93
106
% rsd-triplicates
3
11
11
11
8
Compost A
nd*
nd
18
62
72
% rsd
21
22
14
Compost B
nd
nd
39
56
87
% rsd
32
5
4
Sand
9
5
9
40
88
% rsd
<1
<1
<1
6
5
*nd = <0.4%
9
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