Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10560806 | Talanta | 2005 | 8 Pages |
Abstract
The effectiveness of internal standardization for simultaneous atomic absorption spectrometry (SIMAAS) was investigated for As and Se determination in urine. Co and Sn were selected as internal standard (IS) candidates based on the evaluation of some physico-chemical parameters related to the atomization. Correlation graphs, plotted from the normalized absorbance signals (n = 20) of internal standard (axis y) versus analyte (axis x), precision, and accuracy of the analytical results were the supportive parameters to choose Co as the most appropriate IS. The urine samples were diluted 1 + 2 to 1.0% (v/v) HNO3 + 80 μg Lâ1 Co2+. The mixture 20 μg Pd + 3 μg Mg was used as chemical modifier and the optimized temperatures for pyrolysis and atomization steps were 1400 and 2300 °C, respectively. The characteristic masses for As (47 ± 1 pg) and Se (72 ± 2 pg) were estimated from the analytical curves. The detection limits (n = 20, 3δ) were 1.8 ± 0.1 and 2.6 ± 0.1 μg Lâ1 for As and Se, respectively. The reliability of the entire procedure was checked with the analysis of certified reference material from Sero AS(Seronorm⢠Trace Elements in Urine). The obtained results showed the matrix interference disallowed the instrument calibration with aqueous standards. The best analytical condition was achieved when matrix-matched standards were used in combination with Co as IS, which improved the recoveries obtained for As. Under this experimental condition, eight urine samples were analysed and spiked with 10 and 25 μg Lâ1 As and Se. The mean recoveries were 96 ± 6% (10 μg Lâ1 As), 95 ± 6% (25 μg Lâ1 As), 101 ± 7% (10 μg Lâ1 Se), and 97 ± 4% (25 μg Lâ1 Se).
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Paulo R.M. Correia, Pedro V. Oliveira,