Manganese content of the cellular components of blood.

We measured the manganese content of whole blood, plasma, platelets, mononucleated cells, polymorphonucleated cells, and erythrocytes. Platelets and blood cells were separated from whole blood by use of discontinuous gradients of colloidal polyvinylpyrrolidone-coated silica (Percoll), and their manganese content was measured by Zeeman graphite furnace atomic absorption spectrophotometry, after digestion with nitric acid and hydrogen peroxide. Erythrocytes account for about 66% of the manganese in whole blood, whereas the "buffy coat"--platelets and leukocytes--accounts for about 30%. The "buffy coat" components turn over more rapidly than do erythrocytes, so their manganese content may better indicate the body's manganese status.