Characterization of the TSI model 3086 differential mobility analyzer for classifying aerosols down to 1nm

Measurement systems for particle sizing starting at 1nm are used to bridge the gap between mass spectrometer measurements and traditional aerosol sizing methods, and thus to enable measurement of the complete size distribution from molecules and clusters to large particles. Such a measurement can be made using a scanning mobility particle sizer equipped with a diethylene glycol growth engine (e.g., TSI Model 3777 Nano Enhancer) along with a condensation particle counter, and a differential mobility analyzer (DMA) appropriate for such small sizes. Previous researchers have used high-resolution DMA (HRDMA) and also the TSI Nano-DMA (Model 3085) in such a scanning mobility particle sizer system. In this study, we evaluate the performance of the recently introduced TSI 1nm-DMA (Model 3086). The transfer function was characterized using 1-2nm monomobile molecular ion standards. The same measurements were repeated on a TSI Nano-DMA, with good agreement to previously published values. From the measured transfer function, the resolution of each DMA model was determined as a function of particle size and sheath flow rate. Resolution of the TSI 3086 in the 1-2nm range was 10-25% higher than the TSI 3085. Measured resolutions of the TSI 3086 were 10-20% lower than theoretically predicted values, whereas those of the Model 3085 were 0-10% lower.Copyright (c) 2018 TSI Inc.