It was postulated that a gold generator and a platinum collector would provide the optimum sensor performance. Therefore, platinum was electroplated onto one comb of a gold IDE to create a Au-Pt IDE based Sensor. This was undertaken using a commercial platinum plating bath as described in the experimental section. The datasheet defined optimum parameters for plating were a current bias of 1 A/dm 2 of electrode surface to give a deposition rate of 5 µm/hr. As the surface area of one comb of electrodes was 1.08 x 10 -7 dm 2 , the applied current was set at 0.108 µA. It was found that the optimum deposition thickness was 100 nm, as this was the thickness at which complete coverage of the electrode was observed, therefore deposition was carried out for 60 seconds. Following the plating procedure, an array of characterisation techniques were applied to determine how well the platinum had deposited on the surface. Initial characterisation was carried out using SEM and energy dispersive x-ray (EDX) spectroscopy to characterise the efficacy of the deposition process. Both techniques were performed on both a gold-gold IDE and a gold-platinum IDE for comparison. Figure shows the SEM and EDX, respectively, of a gold-gold IDE. From SEM analysis it was determined that both the generator and collector combs were approximately the same width (0.75 µm), and the gap was slightly over 1.24 µm. The electrodes shown in the SEM image were electrically independent of each other, such that plating on one of these electrodes should not impact the other electrode. EDX was performed on both electrode combs and spectra were obtained for each. The EDX spectra shown in Figure shows that gold was the dominant species present, indicated by the arrows. The SEM image in Figure was obtained from the platinum plated electrode indicates that approximately 100 nm of platinum was deposited on the collector comb of electrodes. The platinum comb width increased to 874 nm, and subsequently the gap decreased to 1.17 µm. The EDX spectrum for a plated electrode shown in Figure (d) highlights that while gold was still the dominant species, platinum was also present on the surface, indicated by the silver-coloured arrows. The underlying gold was found to be dominant in the EDX spectrum since only a thin layer of platinum was deposited. Thus, the X-rays can penetrate through the platinum layer and detect gold. The penetration was so deep in fact, that the adhesion layer titanium, which was underneath the gold, was also detected in trace amounts. An EDX was also performed on the unplated gold comb of electrodes. This was done as the width of the gold electrodes seemed larger than the non-plated IDE (777 nm vs. 758 nm). The EDX showed that no platinum was present on the gold electrode, and the larger width may have been due to variability in the fabrication process as it utilises optical lithography materials optimised for a 1.5 µm fabrication process. CV was then performed in single mode at the plated comb. Figure (a) shows a comparison of CVs of 1 mM FCA at a gold comb before and after the comb had been plated with platinum. The observed peak shaped behaviour is again a result of diffusional overlap, which resulted in time dependent diffusion-limited mass transfer behaviour and a reduction peak for the oxidised FCA on the reverse sweep at approximately 0.22V. The oxidation peak current at 0.35V increased by approximately 1 nA as a result of the platinum plating consistent with an increased surface area. A significant behaviour change was seen on the platinum coated electrodes, wherein a reduction current was seen between 0 V and 0.1 V. This was determined to be the onset of oxygen reduction. Again, this further indicated that platinum had deposited onto the electrode comb, as platinum reduces oxygen at more anodic potentials than gold. Typical deposition data is shown in the inset of Figure .