Development of a Novel Mass Spectrometric ... - Jacobs University

Results and Discussion
Intens.
[%]
100
327.0
+MS 2 (328)
80
60
Ag
106.8
40
20
0
346.7
126.9
242.9 271.0 299.1
158.8 188.9 214.8 364.7
50 100 150 200 250 300 350 400 450 500 m/z
Figure 3-45 APCI-MS 2 of a silver adducted complex at m/z 328 ion
3.4.6 Tandem MS of PCBs
Tandem MS experiments were performed for the PCBs that appeared in the
negative mode mass spectrum of the waste sample. Similarly, in advance, PCBs
from the Congener standard mix were fragmented. (M-Cl+O) – ions from the two
aforementioned sources were selected and isolated with an isolation width of 0.5
Da and each PCB was subjected to Collision Induced Dissociation (CID). All ions
of different PCBs from both samples suggested a loss of chlorine upon
fragmentation (see figure 3-46 and 3-47). It was noticed that the PCBs are less
liable to fragment. This is also reported for the fragmentation of PCBs. 111,112 In all
cases the MS 2 of the selected PCBs within the standard mix were found identical
to those native in waste sample. Similar to the high mass n-alkane species in some
waste samples, high mass chlorinated compounds demonstrated the production of
very weak or no fragments upon fragmentation. Figure 3-48 shows the MS 2 spectra
of the high mass chlorinated components. This can be attributed to the low
abundance of these components as well as their insufficiency to provide a detailed
fragmentation pattern.
77