Influência de modificadores orgânicos na determinação de chumbo em amostras de suplementos de cálcio por GF AAS

Abstract

The main goal of this study was to evaluate the effect of organic modifiers in the determination of lead in calcium supplement samples by graphite furnace atomic absorption spectrometry (GF AAS). Samples of refined calcium carbonate, dolomite and oyster shell were used in this study. For this purpose different decomposition procedures as well as different modifiers were tested (Pd, citric acid, ascorbic acid, oxalic acid). The temperature program for lead determination was determined according to the results from the atomization and pyrolysis curves. With the use of organic modifiers it was possible to reduce the interference of background. The results of Pb determination, using different decomposition procedures, were compared using analysis of variance. The results using the proposed procedure shown better detection limits that those previously reported in the literature. In addition, the modifiers based on organic compounds are relatively inexpensive. However, in view of the lack of certified reference material the accuracy was evaluated using the addition of analyte and matrix matching techniques for calibration.