Assessment of the Sample Handling Procedures in a Labor-saving Method for the Analysis of Organochlorine Compounds in a Large Number of Fish Samples

A rapid single step clean-up procedure with sulphuric acid oxidation for lipid removal has been assessed by a step-by-step recovery approach for its performance in the analysis of organochlorinated compounds in large numbers of fish samples (muscle). Recovery decreases are essentially due to losses by evaporation but their effect is compensated by correction of the recovery factor of tetrabromobenzene that is used as surrogate. Sample grounding with sodium sulphate provides significant higher concentrations than freeze-drying. Soxhlet extraction for 18 h is sufficient to draw most organochlorine compounds from the samples. Repeatability and reproducibility is smaller than the dispersion between fish of similar length and age from the same lake for all compounds except alpha-hexachlorocyclohexane.