instrumental techniques applied to mineralogy and geochemistry

Alike as two water drops: distinguishing one source of the same substance from another 93
Studies with PETN have shown that batches produced by the same manufacturer
fall within a tight cluster of stable isotope ratio values, distinguishable from other
manufacturers. Therefore, information can be obtained as to whether a suspect sample is
consistent with being produced by a certain manufacturer. The analysis of samples of
ammonium nitrate, gunpowder, TNT and plastic explosive confirmed that there was
indeed a range of values for carbon and nitrogen isotope ratios and that the technique
had the potential for the forensic analysis of explosives (Table 2; Fig.3).
-25
-26
Explosives. Finnigan MAT (1995)
Germany
Russia
Unidentified
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Fire accelerant. Meier-Augenstein (2002)
Varnish
Unknown
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-29
-30
-1 0 1 2 3
15 N AIR ,
FIGURE 3. Values of 15 N vs 13 C measured for actual explosives (Finnigan MAT, 1995) and
fire accelerants (Meier-Augenstein, 2002).
When investigating an intentional fire, its origin and how it propagated can
frequently be established by physical means. But gathering unequivocal evidence that
can be sustained on Court is not always an easy task (Jasper et al., 2002). Traditionally,
arson residues are characterized by GC-MS that gives a "fingerprint" of the organic
compounds of the accelerants employed. This fingerprint can then be used to identify
specific classes of petroleum products by forensic chemists. But this just identifies the
accelerant, not the individual that used it.