Abstract Direct solid sampling method was compared with the conventional wet acid digestion method to simultaneously assay iron and nickel in guarana by high-resolution continuum source graphite furnace atomic absorption spectrometry. Measurements were done with the secondary lines of Fe and Ni. Four digestion procedures using mixtures of HNO3 and H2O2 (procedure A), HNO3 and HCl (procedure B), HNO3, HCl and H2O2 (procedure C) and HNO3, H2SO4 and H2O2 (procedure D) were evaluated. All tested procedures provided quantitative recoveries for Ni, whereas a good recovery for Fe was obtained only with procedure D. Procedure D was chosen for the digestion of all guarana samples. The limit of detection for the direct solid sampling method was 1.004 μg g−1 for Fe and 0.022 μg g−1 for Ni, and the precision ranged from 3.5–20.0% and 2.8–8.0% for Fe and Ni, respectively. Method accuracy was evaluated by statistical comparison between analyte concentrations, obtained by measurements in the solid samples by the proposed method and after the digestion of the samples by procedure D. The validation of the analytical results obtained for the solid and the digested sample was performed by Energy Dispersive X-Ray Fluorescence.

中文翻译：

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使用 HR-CS GF AAS 同时测定瓜拉那 (Paullinia cupana Kunth) 中的 Fe 和 Ni：直接固体分析和湿酸消解程序的比较

摘要 采用高分辨连续源石墨炉原子吸收光谱法，将固体直接取样法与常规湿酸消解法同时测定瓜拉那中的铁和镍。测量是用 Fe 和 Ni 的二次线完成的。对使用 HNO3 和 H2O2（程序 A）、HNO3 和 HCl（程序 B）、HNO3、HCl 和 H2O2（程序 C）以及 HNO3、H2SO4 和 H2O2（程序 D）的混合物的四种消解程序进行了评估。所有测试程序都提供了 Ni 的定量回收率，而 Fe 的良好回收率仅通过程序 D 获得。选择程序 D 来消解所有瓜拉那样品。固体直接取样法的检出限为 1.004 μg g-1 Fe 和 0.022 μg g-1 Ni，精密度范围为 3.5-20.0% 和 2.8-8.0% Fe 和 Ni，分别。方法准确性通过分析物浓度之间的统计比较来评估，该浓度是通过所提出的方法在固体样品中测量获得的，以及在通过程序 D 对样品进行消解后获得的。 固体和消解样品的分析结果的验证通过以下方式进行能量色散 X 射线荧光。