Comparison of four different methods for the recovery of dotriacontane-16,17-14C from small animal respiratory tissue.

The efficiency and accuracy of four different methods of tissue preparation for the recovery of dotriacontane-16,17-14C (DOT-16,17-14C) from rat respiratory tissue were compared by means of liquid scintillation counting. A DOT-16,17-14C standard solution was placed on the respiratory epithelium of the nasal apex, larynx, trachea and main bronchi. Combustion of the lyophilized organs in a Packard sample oxidizer revealed the highest recovery and accuracy (93--100%), sample oxidizing by combustion without lyophilization the lowest recovery and accuracy (73--92%). Tissue solubilization by the commercially available tissue solubilizer TS-1 revealed a better recovery and accuracy (89--95%) than tissue maceration by boiling in methanolic KOH and toluene extraction (74--91%). Depending on the laboratory equipment, lyophilization or tissue solubilization is preferred; maceration and toluene extraction as well as combustion without freeze-drying are disregarded for further investigations because of the cumbersome procedure as well as the low recovery and accuracy, respectively.