An electrothermal atomic absorption method for aluminum analysis in plasma: identification of sources of contamination in blood sampling procedures.

A wide range of reported "normal" values for aluminum concentration in serum and plasma prompted the study of an analytical procedure for aluminum determination by atomic absorption and an investigation of possible sources of contamination, which may contribute to the wide variation in results reported in the literature. A method has been developed utilizing the graphite furnace, which gives linear results over an aluminum concentration range of 2.5 to 100 ng Al/mL and a limit of detection of 0.6 ng/mL. Recoveries of added aluminum from plasma ranged from 89 to 100% over this concentration range. The mean plasma concentration of aluminum found in four healthy volunteers was 2.7 ng Al/mL. Blood sampling devices and heparin can have significant amounts of aluminum contamination, which may explain the large discrepancies in quoted "normal" aluminum values in plasma and serum.