Improving the sensitivity of a multi-collector inductively coupled plasma mass spectrometer via expansion-chamber pressure reduction
Improving the sensitivity of a multi-collector inductively coupled plasma mass spectrometer via expansion-chamber pressure reduction
复制标题
通过膨胀室减压提高多接收器电感耦合等离子体质谱仪的灵敏度
DOI：
10.1039/c8ja00448j
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发表时间：
2019
影响因子：
3.4
通讯作者：
Zhang Tao
中科院分区：
文献类型：
--
作者：
Yuan Honglin;Bao Zhian;Chen Kaiyun;Zong Chunlei;Chen Lu;Zhang Tao
在这项工作中，我们通过使用高速 EH 机械增压泵（EH500，500 m3 h−1，BOC Edwards）结合标准 E2M80 泵（80 m3 h−1，BOC Edwards）增加膨胀室的真空，提高了多收集器感应耦合等离子体质谱系统的灵敏度。真空度从 1.0 mbar 提高到低于 0.5 mbar。重同位素（例如 Pb）的样品离子产率在湿等离子体模式（样品吸收率 113 μL min−1）下从 0.047% 提高到 0.072%，在干等离子体模式（样品吸收率 105 μL min−1）下从 1.35% 提高到 1.84%；所有法拉第杯的背景强度变化均小于 1.3 mV。因此，由于湿锥体设置中的孔口稍大，湿等离子体模式中的样品离子产率比干等离子体模式中的样品离子产率更有效地提高。两种模式下所有测试同位素（包括非传统金属同位素）的准确度与之前发布的数据相同，误差在 2 秒之内。这些结果表明，提高界面真空度对同位素测量的准确性没有影响，并且是提高低元素含量本体溶液分析中同位素成分的可检测性以及使用激光烧蚀采样技术进行测量的空间分辨率的有效方法。这项工作可以为拥有类似设备的实验室在处理低含量样品时提供替代方案。
In this work, we improved the sensitivity of a multi-collector-inductively coupled plasma mass spectrometry system by increasing the vacuum of the expansion chamber using a high-speed EH mechanical booster pump (EH500, 500 m3 h−1, BOC Edwards) in conjunction with a standard E2M80 pump (80 m3 h−1, BOC Edwards). The vacuum was improved from 1.0 mbar to less than 0.5 mbar. The sample ion yield for heavy isotopes, such as those of Pb, was improved from 0.047% to 0.072% in the wet-plasma mode (sample uptake rate, 113 μL min−1), and from 1.35% to 1.84% in the dry-plasma mode (sample uptake rate 105 μL min−1); the variation in the background intensity was less than 1.3 mV for all the Faraday cups. Thus, the sample ion yield in the wet-plasma mode was enhanced more effectively than that in the dry-plasma mode owing to a slightly larger orifice in the wet cone setup. The accuracies for all the isotopes tested, including those of non-traditional metal ones, in both modes were identical to previously published data within an error of 2 s. These results indicate that improving the vacuum at the interface has no effect on the accuracy of isotope measurements and is an effective method for improving the detectability of isotopic compositions for bulk solution analysis with low element contents and the spatial resolution for measurements performed using the laser-ablation sampling technique. This work could provide an alternative for laboratories with a similar device, when tackling samples with low contents.