Laser-induced breakdown spectroscopy (LIBS) of dry residues on a solid substrate is a promising method for microanalysis of liquid samples. In this work, a hydrophilized porous silicon (Si) substrate loaded with gold nanoparticles was applied in LIBS of dry residues for signal enhancement. The porous Si substrate was prepared by a simple wet process, i.e. metal-assisted etching. A 5 μL strontium chloride aqueous solution was dried on the porous Si substrate and the dry residue was analyzed by a single-pulse scheme with a laser energy of 1.5 mJ per pulse. We successfully enhanced the strontium signal intensity over 150 times by using the porous Si substrate instead of a flat Si substrate. We also demonstrated that the signal intensity changed depending on the pore depth of the porous Si. The porous Si has great potential as a substrate for LIBS of dry residues.

中文翻译：

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使用通过金属辅助蚀刻生产的多孔硅基板的激光诱导击穿光谱：以氯化锶水溶液的微分析为例

固体基质上干燥残留物的激光诱导击穿光谱法（LIBS）是一种用于液体样品微分析的有前途的方法。在这项工作中，将载有金纳米颗粒的亲水化多孔硅（Si）基板应用于干残留物的LIBS中，以增强信号强度。通过简单的湿法制备多孔Si衬底，即金属辅助蚀刻。将5μL氯化锶水溶液在多孔Si基板上干燥，并通过单脉冲方案以1.5 mJ /脉冲的激光能量分析干燥残留物。通过使用多孔硅衬底代替平坦的硅衬底，我们成功地将锶信号强度提高了150倍。我们还证明了信号强度随多孔硅的孔深而变化。多孔硅作为干燥残留物LIBS的基材具有巨大潜力。