Palladium(II), magnesium(II), and barium(II) nitrate combinations for matrix modification in electrothermal atomic absorption measurement of total selenium in human urine.
Electrothermal atomic absorption spectrometry with a temperature-stabilizing platform and palladium(II) nitrate-magnesium nitrate-barium nitrate matrix modifier combination was used to measure total selenium concentrations in 0.5-ml samples of human urine. The method was validated by analysis of desiccated, standard urine samples (SRM 2670) from NIST. The peak height response was linear from 0 to 150 micrograms Se/liter urine with a sensitivity of 0.001 absorbance unit/micrograms Se/liter and a detection limit of 6 micrograms Se/liter (P = 0.05) for a single measurement. Total urinary selenium concentrations and urine volumes of 24-h samples from 28 healthy adult subjects on self-selected diets and living in San Angelo, Texas were measured. Daily total urinary excretions of 16 male and 12 female subjects (mean +/- SD) were 28 +/- 26 and 34 +/- 25 micrograms Se/day, respectively. A single subject taking 300 micrograms Se/day in the form of aqueous SeO2 as a dietary supplement excreted 232 micrograms Se/day. The unsupplemented subjects' daily selenium excretions correspond to a mean dietary intake of approximately 60 micrograms/day.
Department of Chemistry, Angelo State University, San Angelo, Texas 76909.
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Drake
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Hain
D000328:Adult; D017609:Barium Compounds; D005260:Female; D006801:Humans; D007202:Indicators and Reagents; D017616:Magnesium Compounds; D008297:Male; D009566:Nitrates; D010165:Palladium; D012016:Reference Values; D012643:Selenium / Q000652:urine*; D012680:Sensitivity and Specificity; D012727:Sex Characteristics; D013054:Spectrophotometry, Atomic / Q000379:methods
D017609:Barium Compounds; D007202:Indicators and Reagents; D017616:Magnesium Compounds; D009566:Nitrates; C090639:palladium nitrate; D010165:Palladium; C018330:magnesium nitrate; D012643:Selenium; C023545:barium nitrate