Wroclaw University of Technology, Chemistry Department, Analytical Chemistry Division, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland.
Food Chem. 2014 Mar 1;146:220-5. doi: 10.1016/j.foodchem.2013.09.054. Epub 2013 Sep 18.
Six sample preparation procedures, i.e., the total decomposition in a HNO3 and H2O2 mixture by microwave-assisted or hot-plate heating, a partial decomposition by means of solubilisation in aqua regia or tetramethyl ammonium hydroxide and simple dissolution in diluted HNO3 or in H2O, for the determination of the total content of Ba, Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, P, Pb, Sr and Zn in slim instant coffees using inductively coupled plasma optical emission spectrometry were compared. The performance of procedures was determined based on the precision and the accuracy of results and limits of detection of elements. It was found that the extraction with aqua regia provides the best results, i.e., limits of detection of elements within 0.11-108ngmL(-1), the precision of 0.6-5% and the accuracy better than 5%. Elements' concentrations agree with those after the wet digestion in the HNO3 and H2O2 mixture, therefore this procedure is a simple and fast alternative to complete sample decomposition procedures and can be easily applied for routine analyses. Six commercial slim coffee products were analysed with the proposed procedure.
六种样品制备程序，即通过微波辅助或热板加热将总分解在 HNO3 和 H2O2 混合物中，通过在王水或四甲基氢氧化铵中部分分解和简单溶解在稀 HNO3 或 H2O 中，用于电感耦合等离子体发射光谱法测定速溶咖啡中总含量 Ba、Ca、Cd、Cr、Cu、Fe、Mg、Mn、Ni、P、Pb、Sr 和 Zn。基于元素的精密度和准确度以及检测限来确定程序的性能。发现王水萃取提供了最佳结果，即元素检测限在 0.11-108ngmL(-1) 范围内，精密度为 0.6-5%，准确度优于 5%。元素浓度与在 HNO3 和 H2O2 混合物中的湿法消化后一致，因此该程序是完全分解样品程序的简单快速替代方法，可轻松应用于常规分析。用建议的程序分析了六种商业速溶咖啡产品。
