The magnitude of the current steps due to blocking collisions is shown to be proportional to the square of the particle size, the concentration of the redox mediator, and inversely proportional to the size of the indicator electrode. A theoretical model and a simple analytical expression have been developed that allow for estimation of the average value of the current step magnitude in blocking collisions. Thus, it is now possible to directly relate the size of the analyte to the size of the average current step without worrying about the edge effect. It is proposed that by using the developed model and equations one could monitor the state of analyte species in solution, i.e., whether it is aggregated or not. (C) 2017 Elsevier Ltd. All rights reserved.