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Oil Spill identification - Round Robin 20045 
Zeit [min] gc 
Zeit [min] 
Fig- 4: Gas-chromatograms of samples source I and source II (RIZA) 
The distribution of n-alkanes in source I (blue) and source II (red) is 
totally different: 
If, for example, the peak heights of nC14, nC15, n-C16 and n-C17 are 
divided by either the peak height of the lower boiling n-C11 or the 
higher boiling n-C22, then differences between 20 and 30% are found 
in the ratios of these peaks. These differences -found in the main 
constituents of the oils- are beyond analytical error. 
The relation of the two spill samples to the two possible source samples 
is perfectly visualized by the percentage weathering (PW)-plots 
produced by SKL: no differences except those caused by evaporation 
are recognized, when the spill samples are compared with source I. But 
compared with source II, alkanes of the spill samples are 20 to 30% too 
high in the region C16 to C19.