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Finally, a newly developed clean-up procedure removed other interfering pollutants 
such as PCB completely. A full validation of the methods and intercomparison 
including high resolution MS showed, that all methods were comparable within 10- 
20 %, which is excellent for trace analysis of a extremely complex compound class. 
Limits of detection were around 1 ng PCA absolute corresponding to ca. 1 ng/g fish 
liver and 2-8 ng/g sediment. Linear ranges of two orders of magnitude were achieved. 
Recoveries were typically between 80-100 %. 
Commercial technical PCA mixtures were characterised as a first step. Cn and 
Ci2-compounds contribute ca. 67-82 % to the total sPCA amount. Precision of the 
formula/congener group determination was about 1 %. The average chlorine content and 
molecular weight were the main factors of differentiation. ECNI overestimated the 
chlorine content compared to available supplier information. However, NICI with 
CH4/CH2C12 confirmed it within 1-2.5 %. 
2.1.5 Quantification of chlordanes 
The analysis of chlordane compounds is well established and mainly carried out by 
ECNI mass spectrometry with low resolution instruments. Usually, the four 
representatives cis/trans-chlordane and cis/trans-nonachlor as well as the main 
metabolites of cis/trans-chlordane are quantified. Some unusual chlordane 
representatives such as MC5 and MC7 were also determined in this project. Chlordane 
analysis contained the following elements: The extraction and clean-up method was 
identical to those for PCAs. All main chlordane compounds were present in the PCA 
fraction. Gas chromatographic separation was carried out on the same capillary as 
PCAs. Quantification was carried out by conventional ECNI according to a validated 
method. 
A method based on EI-MS/MS was also developed to check for possible systematic 
errors concerning quantification of sediments. It had comparable detection limits for 
most compounds. The same ECNI quantification technique for sediment analysis was 
used on two mass spectrometers from different supplier. No significant difference