Measurements of Particle Loss Functions in a Differential Mobility Analyzer (TSI,Model 3071) for Different Flow Rates

Particle losses in a differential mobility analyzer (TSI, Model 3071) caused by diffusive deposition and Brownian diffusion are measured for particles in the diameter size range between 3 and 100 nm. For small sampling and aerosol flow rates (0.3 liters/min) at 20 nm, nearly 50% of the primary particles are lost; and for 2 liters/min, the particle losses have to be considered in the diameter size range below 30 nm (50% at 7 nm). From the measured penetration values, an effective tube length is derived which is useful to calculate particle losses for other flow rates through the analyzer.