DETECTION OF POLYCHLORINATED-BIPHENYLS BY PHOTOACTIVATED FLUORESCENCEAND BY SENSITIZED LASER PHOTOLYSIS

Fluorescence resulting from the photoactivated reaction between polych lorinated biphenyls (PCBs) and diphenylamine in isopropanol solution w as exploited for PCB detection. Photoactivation was performed in 10 mi n with 252 nm light from a xenon are lamp; the same light source, filt ered at 365 nm, provided the excitation energy during fluorescence mon itoring. Small-volume cuvettes were fabricated to enable analysis of 5 mu l samples, and a glass fiber bundle was used to transmit the total emission for detection with a photomultiplier tube to attain a detect ion limit of 0.1 mu g/ml. Sensitization of the PCB photolysis was also investigated by introducing phenothiazine to the reacting solution. A helium-cadmium laser system accomplished the sensitized photolysis in 5 min and the resulting fluorescence was monitored with a fluorometer to allow analysis of 50 mu l samples at 0.05 mu g/ml Both techniques can differentiate between PCBs and non-PCB oil and have been demonstra ted to be applicable for analyzing extracts from spiked soil samples.