Separation of polychlorinated biphenyls from chlorinated pesticides using aminopropyl bonded-phase cartridge and determination by GC-ECD

Gas chromatography of polychlorinated biphenyls and chlorinated pesticides in water samples is carried out after adsorption from a 25-500 mt sample, o n a cartridge containing 100 mg aminopropyl-bonded porous silica. The clean -up step in which the PCBs and chlorinated pesticides are separated in diff erent eluates is achieved by passing 25 mt of 40 % aqueous methanol through the NH2 Sep-Pak cartridge. The PCBs are desorbed with 500 mu L ethylacetat e, which is concentrated and analysed by GC-ECD. The average recovery at 1 ppb is > 97 % with a standard deviation < 2. The limits of detection are 0. 1 ng mu L-1 and 5 pg mu L-1 respectively for Cl-3-PCB and Cl-8-PCB congener s. In the separation of PCBs from the chlorinated pesticides tested in this work, only the Aidrin is adsorbed for 60 % with the PCBs by the NH2 Sep-Pa k cartridge. The method described is rapid,simple and reproducible.