Abstract Iodine is an essential element, important for normal thyroid function. Due to the frequency of health problems associated with its insufficient intake, new or additional sources of iodine have to be investigated. One of them could be iodine enriched plants. Before introduction into the human diet, the iodine content must be known as precisely as possible. A method of iodine determination in various plant samples by inductively coupled plasma mass spectrometry (ICP-MS) after alkaline microwave extraction was optimized. Among the tested ratios between TMAH and water, the ratio 1:5 was found to be optimal, using the following temperature program: 20 min ramp to 200 °C and 5 min hold on 200 °C. For measurements, 0.1% TMAH solution was chosen as optimal, using helium in the collision cell. A calibration line, for which standards were prepared in 0.1% TMAH, can be used for quantitative determination of iodine content. Measurement uncertainty was estimated to be around 30% for samples with low iodine content (around 0.2 μg I/g) and below 7% for samples with higher iodine content (0.7 μg I/g). Detection limits were 20 ng/g of sample or less and good repeatability of the measurements and linearity over a wide concentration range were found. The results obtained by the optimized method were compared to those obtained with an independent method (k0-INAA), and they showed very good agreement, proving the accuracy of the determination by ICP-MS. Finally, iodine content was determined in samples with different matrices: pea seeds, pumpkin seeds and buckwheat achenes, from plants foliar sprayed with iodide or iodate solutions at the time of blooming.

中文翻译：

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碱性微波萃取后ICP-MS测定植物中的碘

摘要 碘是一种必需元素，对正常甲状腺功能很重要。由于与摄入不足相关的健康问题的频率，必须调查新的或额外的碘来源。其中之一可能是富含碘的植物。在引入人类饮食之前，必须尽可能准确地了解碘含量。优化了碱性微波萃取后电感耦合等离子体质谱 (ICP-MS) 测定各种植物样品中碘的方法。在 TMAH 和水之间的测试比例中，发现 1:5 的比例是最佳的，使用以下温度程序：20 分钟升温至 200 °C，5 分钟保持在 200 °C。对于测量，选择 0.1% TMAH 溶液作为最佳溶液，在碰撞池中使用氦气。校准线，其中标准品用 0.1% TMAH 配制，可用于碘含量的定量测定。碘含量低（约 0.2 μg I/g）的样品的测量不确定度估计约为 30%，碘含量较高（0.7 μg I/g）的样品的测量不确定度低于 7%。检测限为 20 ng/g 样品或更低，并且在较宽的浓度范围内具有良好的测量重复性和线性。将优化方法获得的结果与独立方法 (k0-INAA) 获得的结果进行比较，结果显示出非常好的一致性，证明了 ICP-MS 测定的准确性。最后，测定了具有不同基质的样品中的碘含量：豌豆种子、南瓜种子和荞麦瘦果，来自在开花时用碘化物或碘酸盐溶液喷洒叶面的植物。可用于碘含量的定量测定。碘含量低（约 0.2 μg I/g）的样品的测量不确定度估计约为 30%，碘含量较高（0.7 μg I/g）的样品的测量不确定度低于 7%。检测限为 20 ng/g 样品或更低，并且在较宽的浓度范围内具有良好的测量重复性和线性。将优化方法获得的结果与独立方法 (k0-INAA) 获得的结果进行比较，结果显示出非常好的一致性，证明了 ICP-MS 测定的准确性。最后，测定了具有不同基质的样品中的碘含量：豌豆种子、南瓜种子和荞麦瘦果，来自在开花时用碘化物或碘酸盐溶液喷洒叶面的植物。可用于碘含量的定量测定。碘含量低（约 0.2 μg I/g）的样品的测量不确定度估计约为 30%，碘含量较高（0.7 μg I/g）的样品的测量不确定度低于 7%。检测限为 20 ng/g 样品或更低，并且在较宽的浓度范围内具有良好的测量重复性和线性。将优化方法获得的结果与独立方法 (k0-INAA) 获得的结果进行比较，结果显示出非常好的一致性，证明了 ICP-MS 测定的准确性。最后，测定了具有不同基质的样品中的碘含量：豌豆种子、南瓜种子和荞麦瘦果，来自在开花时用碘化物或碘酸盐溶液喷洒叶面的植物。