Page 247 - Advances in Forensic Applications of Mass Spectrometry - Jehuda Yinon

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MCounts f30 fueloil#4 file6149.ms RIC all
20
Fuel Oil - GC/MS
15
10
5
0
kCounts f30 fueloil#4 f6214ms2.ms RIC all
350
300
Fuel Oil - GC/MS/MS
250
200
GC/MS/MS results in much more
150 information, thus less reliance on
100 alkanes for HPD identification
50
0
kCounts f30 fueloil#4 f6214ms2.ms Ions: 85 all
50
Alkanes Ion 85 - GC/MS/MS
40
30
20
10
0
1 2 3 4 5 6 7 8
minutes
Figure 5.24 GC/MS vs. GC/MS/MS for home fuel oil reference material.
life of a sample. Samples that have been at the fire scene, or stored, for a
long period of time may still have ignitable liquid residues that can be
definitively detected by GC/MS/MS. A sample of a gallon-size tin can is
shown in Figure 5.25. The top half of the figure is the total ion chromato-
gram (TIC) of this sample. If this were the chromatogram from a GC/FID
analysis for screening purposes, this sample would certainly be dismissed
as negative and not be further analyzed due to the lack of detection of
organic components. The GC/MS chromatographic baseline changes at
various segments are due to programming in the acquisition to improve
sensitivity for compounds eluting in that range. This tin can had been
retrieved from a fire scene and initially analyzed as negative by a laboratory
that used GC/MS. The tin can had seen a considerable amount of heat as
the screw cap spout was lost when the solder melted in the fire. A few
months later it was submitted and analyzed by GC/MS and again found to
be negative. There were a sufficient number of ignitable liquid character-
istics to warrant reanalysis by GC/MS/MS. This tin can was reextracted
directly in its nylon evidence bag using SPME and reanalyzed by
GC/MS/MS. The TIC from the GC/MS/MS analysis illustrates the addi-
tional number of compounds that were detected.
One of the best ion profiles in GC/MS analysis of the tin can was for C3-
benzenes as shown in Figure 5.26. There was some comparability to the same
profile in gasoline but it was not very distinctive. The profile comparison in

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