University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Website: @unf

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NIST 1598

Classification: Reference Material -> NIST -> 1598 -> Bovine serum

Citations 1

"An Automated Microtechnique For Selenium Determination In Human Body Fluids By Flow Injection Hydride Atomic Absorption Spectrometry"
J. Trace Elem. Electrolytes Health Dis. 1990 Volume 4, Issue 1 Pages 41-48
Negretti de Bratter VE, Bratter P, Tomiak A

Abstract: The automation of a flow injection system for the hydride generation of selenium and its subsequent determination by atomic absorption spectrometry (FI-HAAS) is described. Pre-treatment of the sample and the details of the automated equipment are reviewed. For the FI-HAAS selenium analysis a volume of 350 µL of acid-digested sample solution is injected. The online generated hydride is delivery by the gas-liquid separator and is transported together with an Ar stream to the heated quartz cell for the atomic absorption determination. The absolute detection limit is 35 pg Se; the relative detection limit 0.10 µg/L Se. The absolute determination limit in real biological samples is 110 pg Se; the relative detection limit 0.31 µg/L Se. The accuracy of the method was evaluated via analysis of certified standard reference materials. Quality control was made by comparing FI-HAAS and instrumental neutron activation analysis (INAA), as an independent analytical method. Two acid-digestion procedures (in open vessels at atmospheric pressure and bomb-digestion in pressure vessels) were experimentally tested. To determine the effectiveness of the selenium reduction and the completeness of the selenium hydride formation a parallel selenium determination was carried out by means of ICP-AES and FI-HAAS analysis. FI-HAAS was applied for blood serum analysis of children undergoing long-term total parenteral nutrition, as well as of persons with high dietary selenium intake, and for human milk analysis. Human serum or milk (150 µL) is digested overnight with 1 mL of concentrated HNO3, a further 1 mL of HNO3 is added, and the sample is ashed for 1 h at 170°C. After addition of 100 µL of H2SO4 and 50 µL of HClO4, the sample is ashed for a further 1.5 h. Alternatively bomb-digestion is performed for 5 h at 160°C. The digest is diluted to 3 mL with 5 M HCl and heated at 95°C for 30 min for reduction of Se(VI) to Se(IV). A 350 µL portion of this solution is injected into a water carrier stream (2.2 mL min-1) that is subsequently mixed with streams of HCl (2.2 mL min-1) and alkaline 3% NaBH4 (0.44 mL min-1). The reaction mixture is passed into a gas - liquid separator and the H2Se formed is swept by Ar (0.3 l min-1) into a heated silica tube, where it is atomized at 900°C for detection of Se at 196.0 nm. Calibration graphs are rectilinear for 0.87 to 8.7 ng of Se injected and the limit of detection is 0.1 µg l-1. Results for four biological standard reference materials (including NBS Bovine Serum and Oyster Tissue) agreed well with certified values. Results for Se in human serum or milk generally agreed well with those obtained by instrumental NAA.
Selenium Sample preparation Spectrophotometry Automation Detection limit Reference material Calibration Phase separator Volatile generation Method comparison Review Volatile generation