Plasma selenium concentration in healthy Japanese children and adults determined by flameless atomic absorption spectrophotometry.

This study showed a rapid and direct method for determining selenium concentration in plasma by flameless atomic absorption spectrophotometry, and differences in plasma selenium concentration in healthy children and adults. A direct method is possible, since selenium is heat stable in the presence of nickel. With this method, the recovery of selenium added to plasma was 100.3 +/- 5.7%, and the relative standard deviation in repeated determinations of pooled plasma selenium was 3.0% and 6.8%. The plasma selenium concentration in adults was 99.4 +/- 12.5 ng/ml, lower than reported concentrations from the United States and Canada, and higher than those from New Zealand. These variations may reflect dietary habits, bioavailability of selenium compounds in diet, racial difference, or different analytical methods. The mean concentration of plasma selenium at 1 to 6 months of age (51.0 +/- 13.1 ng/ml) was significantly lower than in adults (p less than 0.001); it increased gradually and steadily to the adult level with age. This age-related difference of plasma selenium level is similar to that reported previously.