Abstract A parallel plate differential mobility analyzer (DMA) having 100 independent current collectors is calibrated to relate the axial distances Ln between the inlet slit and the detector position to the particle mobility Z at given voltage difference V and sheath gas flow rate Q. Calibrating species are tetraheptylammonium bromide clusters (THABr) and polyethylene glycol (PEG35k, 5 nm in diameter), generated by a bipolar electrospray source, and purified in a cylindrical DMA. Gaussian fitting of the raw discrete mobility spectra in the form of ion current In versus collector position Ln , In (Ln ), yield the mean value Lo of the collector position maximizing the signal for a given ion. The many (Z,V,Lo ) triads obtained at given Q from many different DMA voltages and standard mobilities collapse into a single 1/(ZiVj ) vs Lo curve when slight adjustments are made to the Zi . For different flow rates, Q/(ZiVj ) vs. Lo curves collapse also, as long as the peaks are moderately narrow. However, for sufficiently small Q/Z, the THABr cluster peaks become broad, and the curves Q/(ZiVj ) vs. Lo cease to collapse precisely. In contrast, the data for PEG show that this behavior is not a low-Q (Reynolds number) effect from the growth of the two lateral boundary layers, but is rather due to the broad and non-Gaussian peak shapes obtained at low Q or high Z. The calibration is accordingly unaffected by the Reynolds number. This simplicity was unexpected, given the three-dimensional flow in this DMA with growing lateral boundary layers. Copyright © 2020 American Association for Aerosol Research

中文翻译：

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在具有 100 个独立离子收集器的差分迁移率分析仪中即时采集高分辨率迁移谱：仪器校准

摘要 校准具有 100 个独立集电器的平行板差分迁移率分析仪 (DMA)，将入口狭缝和检测器位置之间的轴向距离 Ln 与给定电压差 V 和鞘气流速 Q 下的粒子迁移率 Z 相关联。是四庚基溴化铵簇 (THABr) 和聚乙二醇 (PEG35k，直径 5 nm)，由双极电喷雾源生成，并在圆柱形 DMA 中纯化。以离子电流 In 与收集器位置 Ln 、In (Ln ) 的形式对原始离散迁移率谱进行高斯拟合，产生最大化给定离子信号的收集器位置的平均值 Lo。许多 (Z,V, Lo) 在给定 Q 下从许多不同的 DMA 电压和标准迁移率获得的三元组，当对 Zi 进行轻微调整时，会折叠成一条 1/(ZiVj ) vs Lo 曲线。对于不同的流速，Q/(ZiVj ) vs. Lo 曲线也会崩溃，只要峰值适度窄。然而，对于足够小的 Q/Z，THABr 簇峰变宽，曲线 Q/(ZiVj ) vs. Lo 不再精确地坍塌。相比之下，PEG 的数据表明，这种行为不是来自两个横向边界层生长的低 Q（雷诺数）效应，而是由于在低 Q 或高 Z。因此校准不受雷诺数的影响。考虑到该 DMA 中的三维流动以及不断增长的横向边界层，这种简单性是出乎意料的。