25 
Aromatics are not suitable for the discrimination among HFO samples because 
| \ identical or at least very similar clusters of aromatic hydrocarbons are found in 
most commonly used HFOs. 
There are few HFOs which do not contain cracking products (HFOs produced in refineries 
without cracking units). Consequently, their aromatic clusters are different: although the GCs 
of the two oils given in Figure 21 look similar, the two samples can be readily differentiated 
by their aromatic patterns: the typical clusters of aromatics from cracking processes are only 
found in the right-hand sample. 
Fig. 21: GCs and mass chromatograms of masses 192 and 234 of two different HFOs. 
These two samples were taken from the cargoes of different tankers (transport of HFO) but 
have been produced from the same type of crude oil (Russian export blend). Consequently, 
they are hardly discriminable by their biomarker patterns (Fig. 22).