TY - JOUR
T1 - Ion-transfer electrochemistry at arrays of nanointerfaces between immiscible electrolyte solutions confined within silicon nitride nanopore membranes
AU - Scanlon, Micheál D.
AU - Strutwolf, Jörg
AU - Blake, Alan
AU - Iacopino, Daniela
AU - Quinn, Aidan J.
AU - Arrigan, Damien W.M.
PY - 2010/7/15
Y1 - 2010/7/15
N2 - Ion transfer across interfaces between immiscible liquids provides a means for the nonredox electrochemical detection of ions. Miniaturization of such interfaces brings the benefits of enhanced mass transport. Here, the electrochemical behavior of geometrically regular arrays of nanoscale interfaces between two immiscible electrolyte solutions (nanoITIES arrays) is presented. These were prepared by supporting the two electrolyte phases within silicon nitride membranes containing engineered arrays of nanopores. The nanoITIES arrays were characterized by cyclic voltammetry of the interfacial transfer of tetraethylammonium cation (TEA+) between the aqueous phase and the gelled organic phase. Effects of pore radius, pore center-to-center separation, and number of pores in the array were examined. The ion transfer produced apparent steady-state voltammetry on the forward and reverse sweeps at all experimentally accessible scan rates and at all nanopore array designs. However, background-subtraction of the voltammograms revealed the evolution of a peak-shaped response on the reverse sweep with increasing scan rate, indicative of pores filled with the organic phase to a certain extent. The steady-state voltammetric behavior at the nanoITIES arrays on the forward sweep for arrays with significant diffusion zone overlap between adjacent nanoITIES is indicative of the dominance of radial diffusion to interfaces at the edge of the arrays over linear diffusion to interfaces within the arrays. This implies that nanoITIES arrays, which occupy an overall area of micrometer dimensions, behave like a single μITIES of corresponding area to the nanoITIES array.
AB - Ion transfer across interfaces between immiscible liquids provides a means for the nonredox electrochemical detection of ions. Miniaturization of such interfaces brings the benefits of enhanced mass transport. Here, the electrochemical behavior of geometrically regular arrays of nanoscale interfaces between two immiscible electrolyte solutions (nanoITIES arrays) is presented. These were prepared by supporting the two electrolyte phases within silicon nitride membranes containing engineered arrays of nanopores. The nanoITIES arrays were characterized by cyclic voltammetry of the interfacial transfer of tetraethylammonium cation (TEA+) between the aqueous phase and the gelled organic phase. Effects of pore radius, pore center-to-center separation, and number of pores in the array were examined. The ion transfer produced apparent steady-state voltammetry on the forward and reverse sweeps at all experimentally accessible scan rates and at all nanopore array designs. However, background-subtraction of the voltammograms revealed the evolution of a peak-shaped response on the reverse sweep with increasing scan rate, indicative of pores filled with the organic phase to a certain extent. The steady-state voltammetric behavior at the nanoITIES arrays on the forward sweep for arrays with significant diffusion zone overlap between adjacent nanoITIES is indicative of the dominance of radial diffusion to interfaces at the edge of the arrays over linear diffusion to interfaces within the arrays. This implies that nanoITIES arrays, which occupy an overall area of micrometer dimensions, behave like a single μITIES of corresponding area to the nanoITIES array.
UR - http://www.scopus.com/inward/record.url?scp=77954646300&partnerID=8YFLogxK
U2 - 10.1021/ac1008282
DO - 10.1021/ac1008282
M3 - Article
AN - SCOPUS:77954646300
SN - 0003-2700
VL - 82
SP - 6115
EP - 6123
JO - Analytical Chemistry
JF - Analytical Chemistry
IS - 14
ER -