Factors affecting determinations of manganese in serum by atomic absorption spectrometry

A method was developed for the routine determination of manganese in serum from healthy human subjects by graphite furnace atomic absorption spectrometry. We controlled the experimental conditions rigorously, from sampling to analysis, to minimize contamination and to conserve diluted samples. We optimized the procedure with two serum Reference Materials, one of which had a manganese concentration very close to what is thought to be the physiological concentration in humans. The best analytical performance was obtained by directly injecting into the furnace serum diluted with an equal volume of a solution containing Triton X-100 and sodium EDTA and calibrating by the standard additions procedure or by a calibration graph constructed in a similar matrix. The Zeeman background correction produced better accuracy and precision than did the classical deuterium correction. Within-run CV for a manganese concentration of 12.7 nmol/L in serum was 7.9%, and between-run precision was 16.1%. The mean (SD) serum manganese concentration in 31 healthy adults was 10.8 (SD 3.0) nmol/L. Sex and age of subjects did not affect concentrations.