Page 280 - Advances in Forensic Applications of Mass Spectrometry - Jehuda Yinon

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3.49
100
m/z 281 -> 46
% MNX
0
3.19
Standards % DNX m/z 265 -> 46
100
0
2.97
100
m/z 249 -> 113
% TNX
0
3.49
100
m/z 281 -> 46
%
0
3.19
100
Sample % m/z 265 -> 46
0
3.06
100
m/z 249 -> 113
%
0
0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50
Retention time (min)
Figure 6.14 Mass chromatograms of LC/MS/MS in the selected reaction mon-
itoring mode of the [M + 75] adduct ions of MNX, DNX and TNX in a standard
–
and in a groundwater sample. (Reprinted with permission from Beller, H.R. and
Tiemeier, K., Use of liquid chromatography/tandem mass spectrometry to detect
distinctive indicators of in situ RDX transformation in contaminated groundwa-
ter, Environ. Sci. Technol., 36, 2060, 2002. © American Chemical Society.)

Detection limits were between 0.032 and 0.047 mg/l. Figure 6.14 shows the
mass chromatograms of LC/MS/MS in the selected reaction monitoring
–
mode of the [M + 75] adduct ions of MNX, DNX, and TNX, in a standard
and in a groundwater sample.
Another study of RDX and its degradation products in water was carried
out using a Micromass Quattro LC (Z-spray) triple quadrupole mass spec-
39
trometer, operated in the electrospray, negative-ion mode. The isocratic
mobile phase was methanol–water (50:50) at a flow rate of 0.2 ml/min, the
HPLC column was a Waters Nova-Pak C column (150 ¥ 2.1 mm, 4 mm
18
particle size). Argon was used as MS/MS collision gas. LC/MS mass spectra
of standards of RDX, MNX, DNX, and TNX (Scheme 6), showed major [M
–
–
–
+ 75] and [M + 45] adduct ions and small [M – H] ions in all 4 compounds.
–
MS/MS of the [M + 75] ions of all 4 compounds yielded daughter ions at
–
m/z 46, NO . Detection limits of RDX and its degradation products in
2
groundwater were 0.1 mg/l.
A series of explosives, including RDX and HMX, were analyzed by ESI-
40
ion mobility spectrometry–mass spectrometry (ESI-IMS-MS). The IMS
© 2004 by CRC Press LLC