The Centre for Analytical Science, The Department of Chemistry, School of Science, Loughborough University , Epinal Way, Loughborough, Leicestershire, United Kingdom , LE11 3TU.
Anal Chem. 2015 Nov 17;87(22):11285-94. doi: 10.1021/acs.analchem.5b02466. Epub 2015 Oct 28.
In recent years, laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) has gained increasing importance for biological analysis, where ultratrace imaging at micrometer resolution is required. However, while undoubtedly a valuable research tool, the washout times and sensitivity of current technology have restricted its routine and clinical application. Long periods between sampling points are required to maintain adequate spatial resolution. Additionally, temporal signal dispersion reduces the signal-to-noise ratio, which is a particular concern when analyzing discrete samples, such as individual particles or cells. This paper describes a novel, two-volume laser ablation cell and integrated ICP torch designed to minimize aerosol dispersion for fast, efficient sample transport. The holistic design utilizes a short, continuous diameter fused silica conduit, which extends from the point of ablation, through the ICP torch, and into the base of the plasma. This arrangement removes the requirement for a dispersive component for argon addition, and helps to keep the sample on axis with the ICP cone orifice. Hence, deposition of sample on the cones is theoretically reduced with a resulting improvement in the absolute sensitivity (counts per unit mole). The system described here achieved washouts of 1.5, 3.2, and 4.9 ms for NIST 612 glass, at full width half, 10%, and 1% maximum, respectively, with an 8-14-fold improvement in absolute sensitivity, compared to a single volume ablation cell. To illustrate the benefits of this performance, the system was applied to a contemporary bioanalytical challenge, specifically the analysis of individual biological cells, demonstrating similar improvements in performance.
近年来，激光烧蚀-电感耦合等离子体质谱（LA-ICPMS）在生物分析中变得越来越重要，因为需要在微米分辨率下进行超痕量成像。然而，尽管这项技术无疑是一种有价值的研究工具，但目前技术的冲洗时间和灵敏度限制了其常规和临床应用。为了保持足够的空间分辨率，需要在采样点之间保持较长的时间间隔。此外，时间信号分散会降低信噪比，这在分析离散样品（如单个颗粒或细胞）时尤为重要。本文介绍了一种新颖的双体积激光烧蚀池和集成的 ICP 火炬设计，旨在最大限度地减少气溶胶分散，以实现快速、高效的样品传输。整体设计采用短而连续直径的熔融石英导管，从烧蚀点延伸到 ICP 火炬，并进入等离子体底部。这种布置消除了对氩气添加的分散组件的需求，并有助于使样品与 ICP 锥体孔保持同轴。因此，理论上减少了样品在锥体上的沉积，从而提高了绝对灵敏度（单位摩尔的计数）。这里描述的系统分别在全宽半高、10%和 1%最大时，实现了 NIST 612 玻璃的冲洗时间为 1.5、3.2 和 4.9ms，与单体积烧蚀池相比，绝对灵敏度提高了 8-14 倍。为了说明这种性能的优势，该系统应用于当代生物分析挑战，特别是单个生物细胞的分析，展示了类似的性能改进。
