DETERMINATION OF CHLOROBIPHENYLS, WITH THE SEPARATION OF NON-ORTHO, MONO-ORTHO AND DI-ORTHO CHLORO CONGENERS IN FISH AND SEA MAMMALS

A method for the preparation, clean-up and separation of chlorobipheny ls (CBs) into fractions containing non-ortho CBs, mono-ortho CBs and d i-tri-ortho CBs is given. Methods of clean-up by gel permeation, sapon ification and sulphuric acid impregnated silica gel are compared. High ly chlorinated CBs were shown to decompose under alkaline hydrolytic c onditions. The cleaned-up samples were fractionated using a 250 mm pyr enyl liquid chromatographic column and determined by GC-ECD and GC-NIC IMS. The limit of determination was 10-50 pg kg(-1) (wet weight) for a 10-g sample and the overall long-term variance for the method was les s than or equal to 15%.