Brunnbauer Lukas, Gibbs David Ken, Günther Detlef, Limbeck Andreas
TU Wien, Institute of Chemical Technologies and Analytics Getreidemarkt 9/164 1060 Vienna Austria
ETH Zurich, Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich Vladimir-Prelog-Weg 1 8093 Zürich Switzerland.
J Anal At Spectrom. 2025 Jun 30;40(8):2179-2186. doi: 10.1039/d5ja00172b. eCollection 2025 Jul 30.
LA-ICP-MS is a widely used analytical technique for elemental analysis of different solid samples, including carbon-based samples. To compensate for matrix-effects and instrumental drifts during analysis, application of an internal standard is recommended. For carbon-based samples, the application of carbon as an internal standard seems reasonable but is typically not recommended due to the so-called two-phase sample transport where ablated carbon is transported both as particulate and gaseous species. The quantitative deviations in the sensitivity of particulate and gaseous carbon have not been accessible so far but would provide useful insights into the application of carbon as an internal standard. More precisely, if similar sensitivity for particulate and gaseous carbon species is found, application as an internal standard would not be restricted. To investigate this, we analyze the two-phase sample transport of carbon upon ablation of 5 different polymers, which all form different ratios of particulate and gaseous carbon species. Amongst the studied materials, it has been observed that 2 samples provide almost exclusive formation of a gas phase. Correlating these observed signals for selected polymers with the ablated mass of carbon allows us to calculate the sensitivity of gaseous carbon species as 13.8 cts per pg. Using a mass balance approach, we estimated the sensitivity of particulate carbon for the 3 other polymers, where we find significant differences in sensitivity ranging from 1.69 cts per pg to 14.06 cts per pg. This indicates that the sensitivity for particulate carbon species is highly dependent on the sample matrix, resulting in sensitivity differences up to a factor of 7. All in all, the findings of this study support the results of carbon being an inadequate choice for an internal standard in LA-ICP-MS.
激光烧蚀电感耦合等离子体质谱法（LA-ICP-MS）是一种广泛应用于不同固体样品（包括碳基样品）元素分析的技术。为了补偿分析过程中的基体效应和仪器漂移，建议使用内标。对于碳基样品，使用碳作为内标似乎合理，但由于所谓的两相样品传输，即烧蚀的碳以颗粒和气态两种形式传输，通常不建议这样做。到目前为止，颗粒态和气态碳灵敏度的定量偏差尚无法获取，但这将为碳作为内标物的应用提供有用的见解。更确切地说，如果发现颗粒态和气态碳物种具有相似的灵敏度，那么作为内标物的应用将不受限制。为了研究这一点，我们分析了5种不同聚合物烧蚀时碳的两相样品传输情况，这些聚合物都会形成不同比例的颗粒态和气态碳物种。在所研究的材料中，观察到有2个样品几乎完全形成气相。将所选聚合物的这些观察信号与烧蚀的碳质量相关联，使我们能够计算出气态碳物种的灵敏度为每皮克13.8计数。使用质量平衡方法，我们估计了其他3种聚合物颗粒态碳的灵敏度，发现灵敏度存在显著差异，范围从每皮克计数1.69到14.06。这表明颗粒态碳物种的灵敏度高度依赖于样品基体，导致灵敏度差异高达7倍。总而言之，本研究的结果支持了碳作为LA-ICP-MS内标物选择不当的结论。
