Gold nanoparticles show electroactivity: counting and sorting nanoparticles upon impact with electrodes

Gold nanoparticles (AuNPs) in aqueous 0.10 MHCl are shown to be electroactive at oxidising potentials greater than 1.0 V (vs. Ag/AgCl) by means of voltammetric monitoring of AuNP-electrode collisions. The method promises the use of anodic particle coulometry for the detection and characterisation of the AuNPs.