Abstract
A simplified fluorometric method used for the determination of selenium in serum was described. The serum (0.1ml) was digested with 0.3ml of concentrated nitric acid and 0.5ml of 0.75mol/l perchloric acid (at 160°C, for 60-90min), and reduced with 0.5ml of 6 mol/l hydrochloric acid (at 160°C, for 15-30min). The fluorescence reaction was induced by the addition of 2, 3-diaminonaphthalene reagent to the digested sample, and heating at 50°C for 15min. The produced piazselenol was extracted as cyclohexane and its fluorescence was measured (excitation at 377nm, emission at 520nm). All procedure were performed in a single-test-tube and about 50 samples could be assayed within three hours.
With this method, the detection limit of selenium was 7μg/l (0.7ng/tube), within-series accuracies for a 500μg/l standard solution and serum (133.7μg/l selenium) were 1.79% and 2.11%. and that between-series for serum was 5.94%.
Analytical recoveries of 100ng selenium added to 0.1ml of serum were 90.0-112.0% (n=10). Normal levels of selenium in serum obtained from 42 normal adults (21-60yr, male=8, female=34) were 156.7±42.6μg/l (mean±2SD).
