84 
□ Cl, 
Figure 10: CH 4 /CH 2 C1 2 -NICI determination of the formula group patterns of a sPCA mixutre (55.5 % 
chlorine content. A) and of two North Sea dab liver extracts (B, North Sea 54° 15,64 N, 7° 29,79’ E, not 
studied further, C; site NS1, see Table 24). CI34 compounds are clearly visible.