Page 269 - Advances in Forensic Applications of Mass Spectrometry - Jehuda Yinon

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Figure 6.6 Mass chromatograms of a standard mixture of six TNT isomers and
three DNB, five DNT and one TNB isomers at a concentration of 1 mg/mL each.

The mass spectra of DNB, DNT, and TNB isomers were characterized
by molecular ions, namely, at m/z 168 for DNB, at m/z 182 for DNT, and at
m/z 213 for TNB. All three DNB isomers demonstrated the same CID frag-
mentation pattern: loss of NO from the molecular ion. Only 2,4-DNT could
be differentiated in MS/MS-CID from the other DNT isomers by producing
a fragment ion at m/z 165 due to loss of OH. Additional fragment ions in
–
the CID mass spectrum of 2,4-DNT are [M – H O] , [M – NO] , and [M –
–
2
–
NO – CH ] . All the other DNT isomers produced one fragment ion at m/z
3
138 due to [M – NO] .
–
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