Flagan Richard C
Department of Chemical Engineering, California Institute of Technology, Pasadena, California 91125; email:
Annu Rev Chem Biomol Eng. 2014;5:255-79. doi: 10.1146/annurev-chembioeng-061312-103316. Epub 2014 Mar 20.
The differential mobility analyzer (DMA) is a powerful instrument that continuously separates aerosol particles according to their migration velocities in an electric field with high resolution. Because of the low fields employed, the mobility can be related to particle size or ion cross section. Combined with a sensitive detector, such as a continuous-flow condensation particle counter, the DMA enables differential size distribution measurements to be made within minutes to seconds. Over the past few decades, these capabilities have made the DMA a central tool for aerosol characterization in the 10-1,000-nm size range. DMAs have been adapted recently for measurement of particles as small as 1 nm and are now contributing to our understanding of nucleation, nanotechnology, and gas ions. Moreover, the opposed migration classifier, a new approach to differential mobility analysis, expands the dynamic range and shows promise both for increasing resolution beyond present levels and for changing the way that instruments are built. Thus, the DMA continues to advance methods and capabilities for physical characterization at transition from molecules to clusters to particles.
差分迁移率分析仪（DMA）是一种功能强大的仪器，它能在电场中根据气溶胶颗粒的迁移速度以高分辨率连续分离这些颗粒。由于所采用的电场强度较低，迁移率可与颗粒大小或离子横截面相关。与灵敏的探测器（如连续流冷凝粒子计数器）相结合，DMA能够在数分钟到数秒内进行差分粒径分布测量。在过去几十年里，这些功能使DMA成为表征10 - 1000纳米尺寸范围内气溶胶的核心工具。最近，DMA已被改进用于测量小至1纳米的颗粒，目前正在帮助我们理解成核、纳米技术和气体离子。此外，反向迁移分类器作为一种差分迁移率分析的新方法，扩展了动态范围，在提高分辨率超越当前水平以及改变仪器制造方式方面都显示出了前景。因此，在从分子到团簇再到颗粒的转变过程中，DMA继续推动物理表征的方法和能力发展。
