Abstract Solutions containing paramagnetic ions (PMIs) have been widely used in several industrial and agricultural applications. Although the concentrations of these ions in solutions are very important, they are rarely checked due to the high cost of the measurements. In this paper, we demonstrate the viability of 2 MHz time-domain nuclear magnetic resonance (TD-NMR) relaxometer to quantify PMIs in solution. The method was used to quantify the concentration of Co2 +, Cr3 +, Cu2 +, Fe3 + and Mn2 + and is based on linear correlation between the transverse relaxation rate (T2− 1) of the hydrogens of water and PMIs concentration. The method was validated using inductively coupled plasma optical emission spectrometry (ICP-OES), which is the standard method for quantitative elemental analyses. The concentration of PMIs were analyzed between 0.5 and 10 mg·L− 1, with r2 ≥ 0.99 between the two methods. Although the limits of detection (LOD) and quantification (LOQ) of TD-NMR are several orders of magnitude higher than those of ICP-OES, they are in the range of concentration normally found in commercial applications. Therefore, this work demonstrate that TD-NMR can be an affordable alternative for certificate the concentration of PMIs concentration in small laboratory in industrial or agricultural facilities.

中文翻译：

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使用时域 NMR 定量溶液中的顺磁离子。光发射光谱法的优缺点

摘要 含有顺磁离子 (PMI) 的溶液已广泛用于多种工业和农业应用。尽管这些离子在溶液中的浓度非常重要，但由于测量成本高，它们很少被检查。在本文中，我们展示了 2 MHz 时域核磁共振 (TD-NMR) 弛豫仪在溶液中量化 PMI 的可行性。该方法用于量化 Co2 +、Cr3 +、Cu2 +、Fe3 + 和 Mn2 + 的浓度，并基于水氢的横向弛豫率 (T2-1) 与 PMIs 浓度之间的线性相关性。该方法使用电感耦合等离子体发射光谱法 (ICP-OES) 进行了验证，ICP-OES 是定量元素分析的标准方法。PMI 的浓度在 0 之间进行分析。5 和 10 mg·L− 1，两种方法之间的 r2 ≥ 0.99。尽管 TD-NMR 的检测限 (LOD) 和定量 (LOQ) 比 ICP-OES 高几个数量级，但它们处于商业应用中常见的浓度范围内。因此，这项工作表明，TD-NMR 可以成为证明工业或农业设施中小型实验室 PMI 浓度浓度的经济实惠的替代方案。