Accurate measurement of aerosol pH is crucial for understanding atmospheric processes and mitigating haze pollution. However, online detection of aerosol pH is challenging due to the complex composition of single-particle matter and trace components. This study develops a sensitive and selective sensor for the online detection of aerosol pH using surface-enhanced Raman spectroscopy (SERS). A novel Fe₃O₄@SiO₂@Au-p-aminothiophenol (FA-pATP) sensor was fabricated using a layer-by-layer self-assembly method, achieving enhanced uniformity and increased density of SERS-active hotspots. Magnetic aggregation was employed to further amplify the Raman signal. This sensor was integrated into a 3D-printed microfluidic device to facilitate online monitoring of aerosol pH. The FA-pATP sensor exhibited a significant increase in peak intensity ratio with rising pH, demonstrating high sensitivity and responsiveness due to structural changes in the −NH₂ groups of pATP under different pH conditions. The sensor demonstrated a linear pH response ranging from 5 to 11. The 3D-printed microfluidic device, coupled with the FA-pATP sensor, demonstrated notable performance in various environmental media, indicating strong anti-interference capabilities. The proposed sensor shows great promise for real-time online monitoring of aerosol pH, with broad applications in environmental monitoring.

中文翻译：

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使用带有新型磁性 SERS 传感器的 3D 打印微流控设备进行在线气溶胶 pH 值检测


准确测量气溶胶 pH 值对于了解大气过程和减轻雾霾污染至关重要。然而，由于单颗粒物质和痕量成分的复杂组成，在线检测气溶胶 pH 值具有挑战性。本研究开发了一种灵敏且选择性的传感器，用于使用表面增强拉曼光谱 （SERS） 在线检测气溶胶 pH 值。采用逐层自组装方法制备了一种新型 Fe₃O₄@SiO₂@Au-p-氨基硫酚 （FA-pATP） 传感器，实现了增强的均匀性和增加的 SERS 活性热点密度。采用磁聚集进一步放大拉曼信号。该传感器被集成到 3D 打印的微流体设备中，以促进气溶胶 pH 值的在线监测。FA-pATP 传感器随着 pH 值的升高而表现出峰强度比的显著增加，由于不同 pH 条件下 pATP 的 −NH₂ 基团的结构变化，表现出高灵敏度和响应性。该传感器表现出 5 至 11 的线性 pH 响应。3D 打印的微流控器件与 FA-pATP 传感器相结合，在各种环境介质中表现出显著的性能，显示出强大的抗干扰能力。所提出的传感器在实时在线监测气溶胶 pH 值方面显示出巨大的前景，在环境监测中具有广泛的应用。