An increasing number of studies are focusing on the detection and investigation of nanometer-sized particles. One important tool is the Scanning Mobility Particle Sizer (SMPS). In the case of dynamic processes like nucleation events, the lower detection threshold as well as the measurement time are important system parameters. High accuracy of the applied voltage as a function of time during fast scanning is required. Short scan times additionally yield a broadening and smearing of the measured size distribution. Here, the performance of the Nano-SMPS using the new TSI classifier (TSI 3082) in combination with either the nano water condensation particle counter (TSI 3788) or the ultrafine condensation particle counter (TSI 3776) was investigated. The focus of this work is the performance of the system at the lower detection limit as a function of the scan time. Fast scan times as short as 3 s were tested. The reproducibility of the aerosol size distribution and number concentration for different distributions and materials was investigated. The tested substances included different proteins, sucrose and polystyrene latex reference particles. The sizing reproducibility and accuracy for all tested scan times was within 3%. The measured total number concentration was captured with a precision of +/- 3% for all tested scan times. (C) 2015 Elsevier Ltd. All rights reserved.