The performance of differential pulse stripping voltammetry at micro-liquid-liquid interface arrays

Microporous silicon membranes were recently introduced to create hexagonally-patterned arrays of micro-scale interfaces between two immiscible electrolyte solutions (μITIES). In this report we present a simulation study of the application of differential pulse stripping voltammetry (DPSV) using these μITIES arrays for ion sensing. Simulations showed that the stripping current for ion detection was enhanced by use of relatively deep pores (i.e. a low pore aspect ratio) and a viscous organic phase. These factors decrease the speed of escape of the pre-concentrated ion from the organic side of the ITIES. The stripping current initially increased steeply with pre-concentration time but eventually reached a plateau. Experiments performed using a μITIES array with micropores of radius 26 μm, depth of 100 μm and with a gelified organic phase demonstrated the saturation of the stripping peak with increasing pre-concentration time for the DPSV detection of tetraethylammonium ion. The reasons for the saturations are discussed in terms of diffusion coefficients and depth of the micropores.