Abstract

This work proposes the simultaneous determination of chromium and iron in powdered milk samples using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS) and sample digestion in microwave oven using nitric acid and hydrogen peroxide. The method was established using the primary line (357.869 nm) for chromium and the adjacent secondary line (358.120 nm) for iron while employing aluminum as the chemical modifier. The absorbance signals were measured by peak area using three pixels for both elements. Chromium and iron can be determined in powdered milk samples by the external calibration technique with limits of quantification of 28 ng g⁻¹ for chromium and 19 μg g⁻¹ for iron. The precision was evaluated by using a milk sample with chromium and iron concentrations of 0.76 μg g⁻¹ and 151.3 μg g⁻¹, respectively. The results expressed as relative standard deviation (n = 10) were 2.6% for iron and 3.9% for chromium. The method accuracy was confirmed by the analysis of a milk sample by a comparison of results obtained by the proposed method and those found by employing inductively coupled plasma mass spectrometry (ICP-MS). Five samples were analyzed, and the analyte concentrations found varied from 408 to 805 ng g⁻¹ for chromium. Among the five samples, three had an iron concentration lower than 19 μg g⁻¹ and in the other two samples, the iron concentrations varied from 151 to 199 μg g⁻¹.

中文翻译：

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高分辨率连续谱源石墨炉原子吸收光谱法同时测定奶粉中的铬和铁

摘要

这项工作建议使用高分辨率连续谱源石墨炉原子吸收光谱法（HR-CS GF AAS）同时测定奶粉样品中的铬和铁，以及使用硝酸和过氧化氢在微波炉中消解样品。使用铝作为化学改性剂时，铬的主线（357.869 nm）和铁的相邻副线（358.120 nm）建立了该方法。对于两个元素，使用三个像素通过峰面积测量吸光度信号。奶粉样品中的铬和铁可以通过外部校准技术测定，铬的定量限为28 ng g ^{-1，19μgg -1}铁。精度通过使用牛奶样品与0.76微克克铬和铁的浓度评价^-1和151.3微克克^-1，分别。结果表示 为铁的相对标准偏差（n = 10）为2.6％，铬为3.9％。该方法的准确性通过对牛奶样品的分析进行了确认，方法是将所提出的方法获得的结果与采用电感耦合等离子体质谱法（ICP-MS）获得的结果进行比较。分析了五个样品，发现铬的分析物浓度在408至805 ng g ^-1之间变化。在五个样品中，三个样品的铁浓度低于19μgg ^-1在其他两个样品中，铁的浓度在151至199μgg ^{-1之间变化}。