80 
5.4 Results and discussion 
5.4.1 Formula and congener profiles of technical/synthesised PCAs 
Formula and congener profiles were determined by ECNI for all available technical and 
synthesised PC A mixtures due to the following reasons: 
• To determine the mean molecular weight and chlorine content and to compare them 
with the information from the manufacturer, 
• to investigate differences in the formula and congener group pattern between 
manufacturers, and, 
• to enable an investigation of changes in the formula and congener profiles in 
biota and sediments due to enrichment/depletion mechanisms during dispersion, 
transport and bioaccumulation/metabolisation. 
5.4.1.1 sPCA mixtures 
Table 24 gives a survey about the determined chlorine content, mean molecular weight 
and the relative contribution of C10-13 compounds. Figure 4 visualises the differences of 
the formula group composition between technical and synthesised mixtures for the 
carbon chain lengths C10-13 and 5-10 Cl-atoms. Similarities and differences can be 
summarised as follows: 
• C11 and Ci2-compounds contribute ca. 67-82 % to the total amount. 
• Precision of the formula/congener group determination is about ±1 % 
• A cluster analysis showed that average chlorine content and molecular weight 
were the main factors of differentiation (Hiittig and Oehme, 2005). The mixtures 
clustered into two groups, one with a Cl content <61 % and a mean molecular mass 
<400 g/mol and one with >61 % and >400 g/mol. The members of the group with 
<61 % Cl are marked in Table 24. 
• ECNI overestimated the chlorine content compared to available supplier infor 
mation: Range determined 58.5-66.5 %, range specified 49-69 %. The main reason 
is the too low response of Cl3_4 compounds. Their detection is possible with NICI