68 
Chlorine content \%\ 
Figure 7: Dependence of the total response factor (ECNI) on the degree of chlorination for seven 
different sPCA mixtures (A, average of five interday measurements) and nine different MCCP mixtures 
(B: average of three interday measurements). Error bars indicate standard deviations of the determination 
of the chlorine content in x and of the response factor in y. 
Table 14 shows, that the response factor correction works excellent for PCA mixtures 
being part of the correlation function (maximum 7 % deviation) and well for controls 
(deviations 8-35 %). As can be seen from Table 15, this procedure reduces dramatically 
the systematic errors of the method of Tomy et al. (1997), if the chlorine content of the 
reference is not properly selected. It also allows the quantification with the few 
especially synthesised pure PCA-mixtures. Technical products contain stabilisers and 
other additives, which might lead to interferences and systematic errors (Muir et al., 
2000).