The performance of the gold-platinum IDE was further tested by performing CVs in GC mode using FCA as the redox molecule, wherein the platinum comb was kept as the collector electrode to determine if the platinum plating degraded the overall IDE performance. Figure (b) shows a typical CV performed in FCA in GC mode for a gold-gold IDE and a gold-platinum IDE. In this case, the collector was biased at 0 V to reduce the oxidised species produced at the generator. It can be seen that the current has been amplified by approoximatley 5 times with respect to the non-GC mode scans and the CVs show excellent sigmoidal shape in keeping with diffiusionally independent electrodes. A collection efficiency of 91.1% was calculated from the limiting current of the generator and collector scans when both electrodes were gold, which was typical for the 1.2 µm gap IDEs. The same procedure was performed on the IDE where one comb had been plated with platinum. No significant changes were observed for this CV, as the gold electrode behaved as normal. This indicated that the platinum plating did not cause shorting between the generator and collector combs of electrodes. The current at the generator electrode remained the same, which is expected as the surface area of the gold did not change. The current measured at the collector however, increased by 3 nA compared to the gold collector, arising from increased surface area of the plated electrode. As the collector electrode could only measure species produced from the generator, this increase also yielded an enhanced collection efficiency. The collection efficiency of the gold-platinum IDE was calculated as 95.7%, an increase of 4.6% over the gold-gold array. The increase in collection efficiency resulted from increasing the width of the electrode, which subsequently decreased the gap between the generator and the collector electrodes. As previously discussed, increased electrode width and decreased gap size are the main methods of enhancing the efficiency of diffusion-only generator collector devices.