5 g/kg (Table A5). In all cases, recoveries were
(2500 g/kg) beyond two hours of sonication.
near 100%. Precision was best (<4% RSD) for 1,3-
However, the bath at that time was not cooled.
DNB, TNT, and the DNT isomers.
Further kinetic studies with field-contaminated
NG and PETN were not degraded during the
soils are needed to verify that 18 hours of sonica-
extended (18-hour) sonication in a cooled sonic
tion in a cooled sonic bath is not too long for ac-
bath (Table A6). Previously in our lab, we had ob-
ceptable recoveries of NG.
served a decrease in recovery of NG in spiked soils
Using spiked matrices to determine precision
1,200
Ottawa Sand
Blank
1,000
800
600
400
200
0
0
5
10
15
Time (min)
d) Ottawa sand, blank.
1,200
Ottawa Sand
5 g/kg
1,000
800
600
400
200
0
0
5
10
15
Time (min)
e) Ottawa sand, 5 g/kg.
Figure 5 (cont'd). GC-ECD chromatograms of blank and spiked soils used for determination
of method detection limits and spike recovery.
16
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