The benefit of miniaturization towards the nanoscale of electroanalytical systems was evaluated by assessment of the sensitivity of the response. Ion transfer voltammetry across the interface between two immiscible electrolyte solutions (ITIES) was employed as the basis for detection of nonredoxactive ions. The analytical sensitivity increased on miniaturisation of the interface from millimetre-, to micrometre-, to nanometre-scale, with an improvement in sensitivity of more than three orders of magnitude. This is due to the enhanced mass transport via convergent diffusion as the size of the ITIES is minimised. These results illustrate the benefit of miniaturisation of electrochemical detection methods to the nanoscale.