Retention of the metabolized trace elements in biological tissues following different drying procedures. I. Antimony, cobalt, iodine, mercury, selenium and zinc in rat tissues.

Loss of Sb, Co, I, Hg, Se and Zn during freeze-drying and oven-drying at 80, 105 and 120 degrees C were studied in rat tissues that contained metabolized radioactive isotopes. No loss was observed for any of the 6 elements on freeze-drying. However, tissue-specific differences were observed in many cases for Hg, Se, I and Sb on oven-drying. A significant loss of Hg was observed in liver even at 80 degrees C, and for brain at 105 degrees C. Se was lost from whole blood, brain, lung, and muscle at 120 degrees C. Sb was lost from whole blood at 105 degrees C, but from brain, kidney, lung and spleen at 120 degrees C. Iodine was also lost from whole blood, kidney, blood serum, erythrocytes, brain, lung and muscle at 120 degrees C. Although the losses were statistically significant, they remained in most cases between 2 and 10%, with the exception of Hg at 120 degrees C, where the losses in some of the tissues were unpredictable. For urine, freeze-drying and oven-drying at 80 degrees C was found to be relatively safe for Hg and I. At 105 degrees C and above, serious loss of Hg was observed. In this experiment, the elements Zn, Co, Sb and Se were no studied for urine.