5.4.2.2 PCA concentrations 
• Screening by EI-MS/MS revealed that PCA levels were well detectable in all 
samples and a formula group specific analysis by ECNI possible. 
• Total PCA concentrations determined by EI-MS/MS were comparable or up to 
ca. 50 % higher than those obtained by ECNI. The main reason for this deviation is 
the ability of EI-MS/MS to detect compounds with a lower degree of chlorination as 
well as those with chain lengths > C17. 
• Quantification by ECNI was either carried out with a closely matching reference 
standard according to Tomy et al. (Tomy et al, 1997) or with the response factor 
correction mode (Reth et al, 2005). Both methods give comparable results, if 
properly optimised. The procedure of Tomy was applied to samples OS 1-7 and 
NS1-5: 
• sPCA: Chlorine content 59-62 %, applied quantification standard 60 % Cl. 
• mPCA: Chlorine content 55-58 %, applied quantification standard 56 % Cl. 
• The chlorination degree of samples and of technical products did not differ signi 
ficantly (t-test). 
Table 47 in the appendix summarises the determined molar mass and chlorine content 
for all samples from the North and Baltic Sea to enable a comparison with future data. 
In order to ensure comparability with other investigations using ECNI quantification, 
Table 26 summarises both the PCA sum and formula group specific concentrations 
determined by ECNI mass spectrometry. Table 27 lists the results of most of the very 
few PCA determinations in fish world-wide for comparison. Only studies after 1990 
were included. Earlier PCA determinations suffer normally from a proper quantification 
procedure and the reported results are indicative at the best.