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Oil Spill identification - Round Robin 20045 
Results look obviously already much clearer, when the alkanes are 
based on the mean of C20 to C24, as done by NBI: 
Figure 6. Weathering check of the samples 1—4. 
Fjg 7 Here, not only the big difference between source I and source II is 
Weathering check (NBi) perfectly visualized, but also the difference between the two extracts 
and source II (where the difference of extract I is more obvious). NBI's 
conclusion "sample 4 (source II) cannot come from the same source as 
sample 1 (extract I) and sample 2 (extract II)" ( and, of course sample 3 
(source I) is meant here, too) as the differences cannot be explained by 
the weathering effects, seems to be justified. 
The same differences in the n-alkane distribution between source I and 
source II can be observed in the chromatograms shown by SINTEF. 
Fig. 8: 
Gas chromatogrmas ot the two sources 
(SINTEF)