title: Achievement of Diffusional Independence at Nanoscale Liquid-Liquid Interfaces within Arrays.
abstract: In this work, independent radial diffusion at arrayed nanointerfaces between two immiscible electrolyte solutions (nanoITIES) was achieved. The arrays were formed at nanopores fabricated by focused ion beam milling of silicon nitride (SiN) membranes, enabling the reproducible and systematic design of five arrays with different ratios of pore center-to-center distance (rc) to pore radius (ra). Voltammetry across water-1,6-dichlorohexane nanoITIES formed at these arrays was examined by the interfacial transfer of tetrapropylammonium ions. The diffusion-limited ion-transfer current increased with the ratio rc/ra, reaching a plateau for rc/ra ≥ 56, which was equivalent to the theoretical current for radial diffusion to an array of independent nanoITIES. As a result, mass transport to the nanoITIES arrays was greatly enhanced due to the decreased overlap of diffusion zones at adjacent nanoITIES, allowing each interface in the array to behave independently. When the rc/ra ratio increased from 13 to 56, the analytical performance parameters of sensitivity and limit of detection were improved from 0.50 (±0.02) A M(-1) to 0.76 (±0.02) A M(-1) and from 0.101 (±0.003) μM to 0.072 (±0.002) μM, respectively. These results provide an experimental basis for the design of arrayed nanointerfaces for electrochemical sensing.
authors.affiliation: †Nanochemistry Research Institute, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: †Nanochemistry Research Institute, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia.|‡Mechanisation and Automation Research Centre, Malaysian Agricultural Research and Development Institute (MARDI), P.O. Box 12301, 50774 Kuala Lumpur, Malaysia.
authors.forename: Masniza
authors.initials: M
authors.lastname: Sairi
authors.affiliation: §Institute of Analytical and Bioanalytical Chemistry, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
authors.forename: Gregor
authors.initials: G
authors.lastname: Neusser
authors.affiliation: §Institute of Analytical and Bioanalytical Chemistry, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Kranz
authors.affiliation: †Nanochemistry Research Institute, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia.
authors.forename: Damien W M
authors.initials: DW
authors.lastname: Arrigan