Extraction and clean-up procedures for measuring chlorobenzenes in sediments and fish by capillary gas chromatography

A soxhlet extraction technique for recovering chlorobenzenes from sediments and fish is described. The extract is concentrated by evaporation, cleaned up with florisil (sediments) or a combination of alumina, silica gel, florisil and acidified silica gel (fish) before quantitation by capillary gas chromatography with an electron capture detector. Recoveries for all chlorobenzenes are greater than 80%. Detection limits of the technique are approximately 0.05 ng/g (ppb) for penta- and hexachlorobenzene, approximately 0.2 ppb for the tetrachlorobenzenes, approximately 0.4 ppb for the trichlorobenzenes, approximately 5 ppb for the dichlorobenzenes, and approximately 1500 ppb for monochlorobenzene.