The use of anodic particle coulometry (APC) for the sizing and detection of oxidisable metal nanoparticles such as gold or silver have previously been shown to be reliable, albeit destructive. For the first time, the voltammetric sizing and detection of nanoparticles has been accomplished non-destructively, via the reduction of electroactively-tagged silver nanoparticles during particle impacts. Tag-redox coulometry (TRC) thus significantly expands the scope of nanoparticle sizing by particle-impact methods. (C) 2012 Elsevier B.V. All rights reserved.