Determination of lithium in serum and whole blood by graphite furnace atomic absorption spectrometry
A method has been developed for the direct determination of lithium in serum and whole blood by graphite furnace atomic absorption spectrometry using tantalum carbide coated graphite tubes in combination with ammonium nitrate matrix modification. The maximum permissible charring temperature for lithium was raised from 1050 to 1500 °C and the lifetime of the tube was also prolonged for ca. 200 more firings using the tantalum carbide coated graphite tube compared with the conventional pyrolytic graphite coated graphite tube. Matrix interferences from chlorides present in human blood samples were eliminated using the proposed method, which has been used for the determination of lithium in serum and whole blood of normal healthy individuals.