The effects of storage times, temperatures and container types on the accuracy of atomic-absorption determinations of Cd, Cu, Hg, Pb and Zn in whole heparinized blood.

The concentration changes of five different heavy metals in whole blood were tested under a variety of storage conditions. Changes were observed for hourly, daily and weekly periods at four temperatures (-70, -10, 4 and 22 degrees C) and in six different container types, (pyrex and soda glass, two polyethylene, polypropylene, polystyrene and polycarbonate). Rapid, direct-dilution, heated graphite furnace atomic absorption (AA) techniques were developed for analysis of cadmium, copper, lead, and zinc, while mercury was analyzed by the cold vapor flame atomic absorption spectroscopy (FAAS) method. The levels of all metals changed significantly in one week at almost all temperatures in all containers. Concentrations of cadmium, copper and zinc increased probably through leaching processes while lead and mercury decreased through probable hydrolysis and vaporization, respectively. Commercially cleaned polypropylene tubes did not perform significantly better than acid washed vessels. In the absence of better vessels, storage must be as short as possible for meaningful metal concentration determinations.