Changes in PCB congener concentrations and profile in avian liver due to freeze-drying

Freeze-drying is used for the preparation and especially preservation of biological media but can cause dechlorination of organochlorine compounds and potential reductions in concentration through volatilisation. This study investigated the effect of freeze-drying on the measurable levels of 16 polychlorinated biphenyl (PCB) congeners naturally incorporated into avian liver. Freeze-drying significantly increased the concentrations of seven of the congeners and significantly decreased the variability in measurements on replicate samples.