Sequential solid-phase extraction with cyanopropyl bonded-phase cartridgesfor trace enrichment of PCBs and chlorinated pesticides from water samples

Gas chromatography of polychlorinated biphenyls and chlorinated pesticides in water samples has been performed after adsorption from a 50-250 mt sampl e on to a cartridge containing 100 mg cyanopropyl-bonded porous silica. The PCBs are desorbed with 500 mu L ethyl acetate. which is concentrated and a nalysed by gas chromatography with electron-capture detection (GC-ECD). The average recovery of 1 ppb PCB congeners at from distilled water and fro m Marta river water is greater than or equal to 95 % (standard deviation le ss than or equal to 2.5). The average recovery of 20 ppb Aroclor 1260 from Marta river water was greater than or equal to 91 % (standard deviation les s than or equal to 3.5). In the separation of the PCBs from the chlorinated pesticides only aldrin, heptachlor and 4,4'-DDD are adsorbed with the PCBs by the CN Sep-Pak cartri dge. The method proposed is rapid, simple and reproducible.