Abstract The chemical speciation of nanoparticles is technically challenging because of the minute mass of the particles. There is a constant need for more sensitive collection methods and chemical analyses. In this study, we demonstrated the applicability of a surface enhanced Raman scattering (SERS) technique on the rapid and sensitive chemical analysis of individual nanoparticles. SERS technique provides a significant enhancement of the scattering efficiency over traditional Raman spectroscopy. The novelty of the proposed technique is that the SERS substrate is used directly as the sampling substrate of a condensational growth tube (CGT) sampler, which can activate nanoparticles into water droplets and ensure simultaneous inertial sampling and SERS pretreatment. First, we investigated applicability of the method on mono-dispersed (20 nm, 50 nm, or 100 nm) ammonium sulfate (AS) and levoglucosan (LG) particles as model aerosols. The method was then applied to ambient nanoparticles. The successful detection of peaks corresponding to sulfate ν(SO42-) and organics ν(C-H) indicates that our proposed method to combine a CGT sampler and SERS showed a sensitivity high enough to provide deep insights into the chemical speciation of atmospheric nanoparticles as small as 20 nm in diameter.

中文翻译：

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SERS 在凝聚生长后单个 Aitken 模式粒子的化学形态中的应用

摘要 由于粒子的质量很小，纳米粒子的化学形态在技术上具有挑战性。一直需要更灵敏的收集方法和化学分析。在这项研究中，我们证明了表面增强拉曼散射 (SERS) 技术对单个纳米粒子的快速灵敏化学分析的适用性。SERS 技术与传统拉曼光谱相比，显着提高了散射效率。该技术的新颖之处在于直接将 SERS 衬底用作冷凝生长管 (CGT) 采样器的采样衬底, 可以将纳米粒子活化成水滴, 并确保同时进行惯性采样和 SERS 预处理。首先，我们研究了该方法在单分散（20 nm、50 nm、或 100 nm) 硫酸铵 (AS) 和左旋葡聚糖 (LG) 颗粒作为模型气溶胶。然后将该方法应用于环境纳米粒子。成功检测到对应于硫酸盐 ν(SO42-) 和有机物 ν(CH) 的峰表明我们提出的将 CGT 采样器和 SERS 相结合的方法显示出足够高的灵敏度，可以深入了解大气纳米粒子的化学形态，小至直径 20 纳米。