An analytical method was proposed for the quantification of Cd, Pb, Mn, and Fe in ground coffee samples using energy dispersive X‐ray fluorescence (EDXRF) spectrometry. External calibration was possible using the coffee matrix itself as standards with samples previously analyzed by inductively coupled plasma optical emission spectrometry (ICP OES). The ground coffee samples were analyzed in the form of pellets, which were placed in the center of the EDXRF measuring cell for the determination of the analytes. The limits of detection were 62, 55, 86, and 76 μg/kg for Cd, Pb, Fe, and Mn, respectively. Good linearities were obtained for the calibration curves with coefficients of correlation (R) of 0.9959 for Cd, 0.9939 for Pb, 0.9929 for Fe, and 0.9909 for Mn. Precision, evaluated as the relative standard deviation (RSD) of 10 independent measurements of different cataloged samples with an approximate concentration of 400 μg/kg for each analyte, was between 6 and 14% (n = 10), demonstrating that the preparation of the samples in form of pellets was sufficient to perform analyses by EDXRF. The proposed method was applied in the determination of Cd, Pb, Fe, and Mn in ground coffee samples collected in Salvador, Bahia, Brazil. In a parallel comparative procedure, coffee samples were also analyzed by ICP OES after sample pretreatment by acid digestion. A paired Student's t test was carried out (confidence level of 95%, n = 5) and no significant difference was observed between the concentrations obtained by the proposed and comparative methods.

中文翻译：

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使用能量色散X射线荧光光谱法直接直接测定咖啡粉中的Cd，Pb，Fe和Mn

提出了一种使用能量色散X射线荧光（EDXRF）光谱法定量分析咖啡粉样品中Cd，Pb，Mn和Fe的分析方法。可以使用咖啡基质本身作为标准品进行外部校准，并预先通过电感耦合等离子体发射光谱法（ICP OES）分析样品。磨碎的咖啡样品以小球形式进行分析，将其放置在EDXRF测量池的中心以测定分析物。Cd，Pb，Fe和Mn的检出限分别为62、55、86和76μg/ kg。校正曲线获得了良好的线性，镉的相关系数（R）为0.9959，铅的相关系数（R）为0.9939，铁的相关系数（R）为0.9929，锰的相关系数（R）为0.9909。精确，n = 10），表明以小丸形式制备样品足以进行EDXRF分析。该方法用于巴西巴伊亚州萨尔瓦多收集的咖啡粉中镉，铅，铁和锰的测定。在平行比较程序中，通过酸消解样品预处理后，还通过ICP OES分析咖啡样品。进行了配对的Student's t检验（置信水平为95％，n = 5），并且通过提议的方法和比较方法获得的浓度之间没有观察到显着差异。