Division of Analytical Chemistry and Chemical Metallurgy, Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland.
Molecules. 2023 Apr 11;28(8):3374. doi: 10.3390/molecules28083374.
A fully validated inductively coupled plasma optical emission spectrometry (ICP-OES)-based method combined with a simplified sample preparation procedure for the determination of up to 15 elements (Al, Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sr, and Zn) in caffeinated yerba mate (YM) drinks was proposed. Various "green" treatments (acidification or dilution with a HNO solution and direct analysis of untreated YM with or without sonication (US)) that could replace the traditional total sample decomposition before spectrometric measurements were tested and compared. The key selection parameter was the analytical performance of the ICP-OES method obtained with each sample preparation procedure in terms of the precision and the trueness of results and limits of detection (LODs) of elements. It was found that the acidification of YMs with concentrated HNO to 5%, supported by US (10 min, room temperature (RT)), provided the best results, i.e., LODs at 0.11-8.5 ng g, precision below 5%, and trueness better than 5% (97.0%-105% as recoveries). Eleven YM drinks, commercially available on the Polish market, were analyzed with the proposed method. In addition to the mineral content, the concentration of caffeine in all analyzed YMs was determined and compared. Finally, the studies were completed by determining the bioaccessible fraction of selected elements and caffeine in YMs using in vitro gastrointestinal digestion (GID) in order to evaluate the nutritional value/risk assessment of these drinks. Accordingly, the bioaccessibility of nutritious elements (Ca, Fe, Mg, Mn, Zn) and caffeine was within 40%-59%. Except for Mn, it was established that by drinking daily 1 L of YMs, the recommended dietary intakes (RDIs) of the aforementioned essential elements were covered to a low degree (<4.5%). Hence, they are not an important source of these elements in the human diet. On the other hand, potentially toxic elements (Al, Ba, Sr) were found in a relatively inert form. Opposite to minerals, YMs can supply human organisms with quite high amounts of natural caffeine in bioaccessible form (31-70 mg serving).
本文提出了一种完全经过验证的电感耦合等离子体发射光谱法（ICP-OES），结合简化的样品制备程序，可用于测定含咖啡因的巴拉圭茶（YM）饮料中的多达 15 种元素（Al、Ba、Ca、Cd、Cr、Cu、Fe、K、Mg、Mn、Na、Ni、Pb、Sr 和 Zn）。对各种“绿色”处理方法（酸化或用 HNO 溶液稀释，以及直接分析未经处理的 YM 并辅以超声处理（US））进行了测试和比较，这些方法可以替代传统的在光谱测量前对样品进行全分解的方法。关键选择参数是每种样品制备方法获得的 ICP-OES 方法的分析性能，包括结果的精密度和准确度、检出限（LOD）和元素。结果发现，用浓 HNO 酸化 YM 至 5%，并辅以 US（10 分钟，室温（RT）），可获得最佳结果，即 0.11-8.5ng g 的 LOD、低于 5%的精密度和 5%以上的准确度（以回收率计为 97.0%-105%）。用所提议的方法分析了 11 种在波兰市场上销售的 YM 饮料。除了矿物质含量外，还测定并比较了所有分析 YM 中的咖啡因浓度。最后，通过使用体外胃肠道消化（GID）测定 YM 中选定元素和咖啡因的可生物利用部分，完成了这些研究，以评估这些饮料的营养价值/风险评估。因此，有营养元素（Ca、Fe、Mg、Mn、Zn）和咖啡因的生物可利用度在 40%-59%之间。除 Mn 外，研究发现，每天饮用 1 升 YM，对上述必需元素的推荐膳食摄入量（RDI）的覆盖程度较低（<4.5%）。因此，YM 不是人类饮食中这些元素的重要来源。另一方面，潜在有毒元素（Al、Ba、Sr）以相对惰性的形式存在。与矿物质相反，YM 可以为人体提供相当大量的天然咖啡因（每份 31-70mg）。
