In this work we use the ITIES as a model system for the study of interfacial proton transfer in the absence of surface defects common to all solid electrode-electrolyte interfaces, with special attention to the issue of interpreting the standard rate constant 𝑘𝑘 0 . We first compare two different proton acceptors, 2,6diphenylpyridine (log(P) = 5) and 9-methylacridine (log(P) = 3.5), in a single diffusion-limited micropipette voltammetry experiment to explore the distinction between pre-extraction and interfacial proton-transfer pathways and designate a proton acceptor to be suitable for the use as a model system. The asymmetric geometry of the conical pipette leads to different diffusion profiles, which in turn allows us to assign a dominant pathway for proton-transfer for each base from the standpoint of diffusion-limited voltammetry. We determined that 2,6-diphenylpyridine does not pre-extract to an appreciable extent at an aqueous electrolyte pH of 1, whereas 9-methylacridine partitions itself significantly before the start of the experiment such that most of the observed current is carried by 9MAH + . Following this experiment, the conjugate acid salt of 2,6-diphenylpyridine, (2,6-diphenylpyridinium tetrakis(3,5bis(trifluoromethyl)phenyl)borate), was synthesized for use in a "common-ion" nanopipette voltammetry experiment, allowing for the measurement of 𝑘𝑘 0 about a well-defined equilibrium potential for the first time. From this measurement, we obtained values 𝑘𝑘 0 and 𝛼𝛼 equal to 3.0 +/-1.8 cm/s and 0.3 +/-0.2, respectively. We consider the possibility that an interfacial proton acceptor may still indirectly carry the proton across the interface via a neutral aqueous intermediate, and use multiphysics finite-element simulations to quantitatively assess the possible contributions from parallel direct and sequential protontransfer pathways. With these simulation results, we found that the interfacial-direct pathway dominates the current response for a wide range of possible exchange current densities, overpotentials, and partitioning rate constants.