采用高分辨电感耦合等离子体质谱法（HR-ICPMS）直接准确地测定水中的主要元素 Ca、K、Mg 和 Na。
The direct and accurate determination of major elements Ca, K, Mg and Na in water by HR-ICPMS.
机构信息
National Research Council Canada, 1200 Montreal Rd, Ottawa, K1A 0R6, Ontario, Canada.
出版信息
Sci Rep. 2018 Dec 10;8(1):17750. doi: 10.1038/s41598-018-34028-z.
A direct, accurate and precise method is reported for major elements Ca, K, Mg and Na measurements in river and drinking water using a high resolution ICP-MS. Double isotope dilution calibration was used for the determination of Mg whereas the combined standard addition and internal standardization (Sc) was used for Ca, K and Na measurements. The method is validated by analysis fresh water SLRS-5, SLRS-6 and SRM1640a with satisfactory results characterized by high precisions of 0.055% to 0.66% RSD (or 0.29-1.8% relative combined uncertainty) for all four analytes, superior to those reported in earlier studies. As noted, use of internal standard Sc has significantly (3-33 times) improved measurement precisions for Ca, K and Na compared to standard addition calibration alone. The proposed method was applied for the determination of major elements Ca, K, Mg and Na in a candidate drinking water CRM AQUA-1. Values of 1.908 ± 0.007 µg g, 8.27 ± 0.14 µg g, 0.660 ± 0.010 µg g and 13.76 ± 0.05 µg g (u, k = 1) were obtained for Mg, Ca, K and Na in AQUA-1 drinking water, respectively.
本文报道了一种使用高分辨率 ICP-MS 直接、准确、精确测定河流水和饮用水中主要元素 Ca、K、Mg 和 Na 的方法。采用双同位素稀释法对 Mg 进行了测定，而 Ca、K 和 Na 的测定则采用了标准加入和内标（Sc）联合法。该方法通过对淡水 SLRS-5、SLRS-6 和 SRM1640a 的分析进行了验证，结果表明，所有四种分析物的精密度均较高，为 0.055%至 0.66%（或 0.29-1.8%相对综合不确定度），优于早期研究中的报道。如前所述，与单独使用标准加入校准相比，使用内标 Sc 可显著（3-33 倍）提高 Ca、K 和 Na 的测量精密度。该方法应用于候选饮用水 CRM AQUA-1 中主要元素 Ca、K、Mg 和 Na 的测定。在 AQUA-1 饮用水中，Mg、Ca、K 和 Na 的含量分别为 1.908±0.007μg/g、8.27±0.14μg/g、0.660±0.010μg/g 和 13.76±0.05μg/g（u，k=1）。
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