Abstract

Limited sensitivities of some laser-induced breakdown spectroscopy (LIBS) instruments may impair some applications. Although this drawback can be minimized by instrumental improvements, the complexity of operations and cost increases. In this work the principle of conventional dry ashing for sample preparation was evaluated as a simple and low-cost alternative to improve the sensitivity of LIBS analysis. Botanical, agronomic and industrial samples were analyzed. Samples were dry heated and their LIBS emission signals were evaluated. The results suggest the dry heating caused structural changes in samples providing greater availability of the analyte, which resulted in the enhancement of the signals. As proof of concept, the strategy was applied for Sr determination in plant leaves. Two Sr emission lines, enhanced after sample dry ashing were used. The developed methods showed similar performance featuring a good linear range (10 to 70 μg g⁻¹) with coefficient of correlations higher than 0.99. Additionally, the accurate determination of Sr in apple and peach leaves standard materials was achieved.

摘要

某些激光诱导击穿光谱仪（LIBS）仪器的灵敏度有限，可能会损害某些应用程序。尽管可以通过仪器改进来最大程度地减少此缺点，但操作的复杂性和成本会增加。在这项工作中，将常规干灰化用于样品制备的原理作为一种简单且低成本的替代方法进行了评估，以提高LIBS分析的灵敏度。分析了植物，农艺和工业样品。将样品干燥加热并评估其LIBS发射信号。结果表明，干热导致样品的结构发生变化，从而提供了更高的分析物利用率，从而增强了信号强度。作为概念证明，该策略适用于植物叶片中Sr的测定。使用了两条干法灰化后增强的Sr发射线。^-1）的相关系数高于0.99。此外，还可以准确测定苹果和桃叶标准物质中的Sr。