Photolysis of polychlorinated biphenyls by solid-phase microextraction -: On-fibre versus aqueous photodegradation

The photodegradation kinetics of polychlorinated biphenyls on-fibre is described. The utilisation of solid-phase microextraction (SPME) fibres to monitor photolysis pathways and determine photoproducts constitutes a new approach that exploits the solvent-free aspect and concentration possibilities of this technique. Direct photolysis of aqueous solutions containing polychlorinated biphenyls (PCBs) was also undertaken and SPME was used in this case for photoproduct extraction purposes. Reductive dechlorination was the main decomposition mechanism in both procedures. Less-chlorinated biphenyls are the principal photoproducts and, among these, some toxic coplanar species have been detected. The influence of irradiation time was evaluated for both treatments. SPME was found to be a good choice for the extraction of photoproducts in experiments conducted in the classical way (extraction after photolysis). Moreover, it is demonstrated that photolysis of PCBs on fibre is realistic and provides the possibility of evaluating the phototransformation of these pollutants at environmental levels. (C) 2002 Elsevier Science B.V. All rights reserved.