As one of the most widely used techniques for concentration determination of trace elements in coal, inductively coupled plasma mass spectrometry (ICP-MS) has also been used in several studies for the determination of mercury concentration in coal. ICP-MS after closed-vessel microwave digestion and a Milestone DMA-80 are employed in this study to determine the mercury concentration in coal. Three NIST standard references of coal samples were selected as references to verify the accuracy of the test results. The Au rinse solution (200 μg/L, 5% HNO₃) can diminish mercury memory effects to a blank level within 80 seconds. The results showed that ICP-MS can accurately determine the mercury content in mercury standard solutions, but the mercury concentration in most NIST samples after microwave digestion is lower than the detection level of the ICP-MS. The inaccuracy may be due to volatilization of mercury during solid sample digestion process. By contrast, the determined concentrations in NIST samples by the Milestone DMA-80 are very close to the verified values. Therefore, ICP-MS is not recommended to analyze mercury in coal after digestion even in a closed-vessel digestion system, but the mercury direct analyzer (without digestion) is recommended to analyze mercury in coal.

中文翻译：

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DMA-80和ICP-MS结合封闭容器微波消解法测定煤中汞的比较

作为用于测定煤中痕量元素浓度的最广泛使用的技术之一，电感耦合等离子体质谱法（ICP-MS）也已用于确定煤中汞浓度的多项研究中。这项研究采用封闭容器微波消解后的ICP-MS和Milestone DMA-80来确定煤中的汞浓度。选择了三个NIST煤样品标准参考作为参考，以验证测试结果的准确性。在Au漂洗溶液（200  μ克/升，5％HNO ₃）可以在80秒内将汞记忆效应降低到空白水平。结果表明，ICP-MS可以准确测定汞标准溶液中的汞含量，但大多数NIST样品经微波消解后的汞浓度均低于ICP-MS的检测水平。这种误差可能是由于固体样品消化过程中汞挥发所致。相比之下，由Milestone DMA-80在NIST样品中确定的浓度非常接近验证值。因此，即使在封闭容器消化系统中，也不建议使用ICP-MS分析消解后煤炭中的汞，但建议使用汞直接分析仪（不消解）来分析煤炭中的汞。