A new sample preparation technique for organochlorines in cod liver oil combining SPE and NP-HPLC with HRGC-ECD

The analysis of semivolatile organochlorines (polychlorinated biphenyls and chlorinated pesticides) in less polluted biomaterials requires specific strategies in controlling the blank in sample preparation. The procedure described here allows to decrease significantly the level of contamination during the clean-up step of fish oil. Solid-phase-extraction (SPE) on LiChrolut EN and normal phase HPLC in the normal- and the backflush-mode were used to reduce the amount of solvents needed and the analysis time compared to established clean-up procedures. With a certified reference material (BCR-CRM 349; Cod Liver Oil) the precision and effectiveness of the new method were validated. Recovery rates of the Internal Standards (PCB 103 and TCN) lay between 75% and 90% at the microg/kg lipid level. The quantitative analyses were carried out by high resolution gas chromatography with electron capture detector (HRGC-ECD).