Zheng Lina, Kulkarni Pramod, Zavvos Konstantinos, Liang Huayan, Birch M Eileen, Dionysiou Dionysios D
Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Cincinnati, OH, USA.
Environmental Engineering and Science Program, Department of Biomedical, Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH, USA.
J Aerosol Sci. 2017 Feb;104:66-78. doi: 10.1016/j.jaerosci.2016.11.007.
Efficient microconcentration of aerosols to a substrate is essential for effectively coupling the collected particles to microscale optical spectroscopies such as laser-induced or spark microplasma, or micro-Raman or infrared spectroscopies. In this study, we present detailed characterization of a corona-based aerosol microconcentration technique developed previously (Diwakar and Kulkarni, 2012). The method involves two coaxial electrodes separated by a few millimeters, one held at a high electrical potential and the other grounded. The particles are collected on the collection (i.e., ground) electrode from a coaxial aerosol flow in a one-step charge-and-collect scheme using corona discharge and electrical precipitation between the two electrodes. Performance of the corona microconcentration method was determined experimentally by measuring collection efficiency, wall losses, and particle deposition density. An intrinsic spectroscopic sensitivity was experimentally determined for the aerosol microconcentrator. Using this sensitivity, we show that corona-based microconcentration is much superior to alternative methods, including filtration, focused impaction using aerodynamic lens, and spot collection using condensational growth. The method offers unique advantages for compact, hand-held aerosol analytical instrumentation.
将气溶胶高效微浓缩到基底上对于将收集到的颗粒有效地耦合到微尺度光学光谱学（如激光诱导或火花微等离子体、微拉曼或红外光谱学）至关重要。在本研究中，我们详细描述了先前开发的基于电晕的气溶胶微浓缩技术（迪瓦卡尔和库尔卡尼，2012年）。该方法涉及两个同轴电极，它们相隔几毫米，一个处于高电位，另一个接地。颗粒通过两步电荷收集方案，利用电晕放电和两个电极之间的电沉淀，从同轴气溶胶流中收集在收集（即接地）电极上。通过测量收集效率、壁面损失和颗粒沉积密度，实验确定了电晕微浓缩方法的性能。通过实验确定了气溶胶微浓缩器的固有光谱灵敏度。利用这种灵敏度，我们表明基于电晕的微浓缩比其他方法（包括过滤、使用空气动力学透镜的聚焦撞击和使用凝结生长的点收集）优越得多。该方法为紧凑的手持式气溶胶分析仪器提供了独特的优势。
