67 
Therefore, this study investigated, if an interpolation was permissible of the dependence 
of the total response factor on the degree of chlorination (Reth et al., 2005). The total 
response factor and chlorine content of a PCA mixture are calculated as follows: 
1. Determination of total PCA signal area from the mass chromatograms of the congener groups i: 
„ , . , ^ ^ area ¡(congener group) 
Relative total CP area = X / x (1) 
area 
¡(ISTD) 
The equal amount of internal standard in sample and reference eliminates its quantity. 
2. The total response factor is calculated as: 
Total response factor (PCA mixture) 
3. The chlorine content is defined as: 
rei. total PCA area (Std.) 
amount PCA (Std.) 
(2) 
Chlorine content (PCA mixt.) = ^ 
rel. area (cong. group ¡) • chlorine content (cong. group ¡) 
rel. total PCA area 
(3) 
The relation between the total response factor and the chlorine content was established 
with seven sPCA-mixtures from different manufacturers (degree of chlorination 51- 
69 %) and nine mPCA (54-58 %) from ICI (UK). A linear correlation was found (see 
Figure 7). It allowed to determine the total response factor of a PCA-mixture or of the 
PCA content of a sample after the determination of the chlorine content according to 
equation (4): 
Total response factor (sample PCAs) = a ■ x + b (4) 
a: slop; b: intercept; x: determined chlorine content 
This total response factor is then used to calculate the total PCA amount of a sample: 
PCA amount (sample)= 
relative total area (sample) 
total response factor (calculated for the sample) 
(5)