A flash thermodesorption-gas chromatography-mass spectrometry technique has
been developed for the determination of polychlorobiphenyls (PCB), especia
lly the highly toxic planar species, in sewage sludge. A modified Curie-poi
nt pyrolyzer was used; in this the flash-desorption temperature was control
led by selecting specific metal alloys for the pyrolysis wire. Samples (3 m
g) were loaded into a quartz tube with the special heating wire wound aroun
d the outer wall. By this means rapid thermal desorption (TDS) was achieved
whereas uncontrolled catalytic breakdown of the analytes was avoided. The
thermodesorption unit was connected via a custom-built interface to the GC-
MS detection system. The average limit of detection was 15 mug kg(-1) sludg
e-more than one order of magnitude better than the legal requirement.