Initial tests with platinum as a collector material indicated that the performance was worse than for bare gold. From the initial H2O2 experiments it was hypothesized that this should not be the case, as platinum outperformed gold. It was determined that the constant bias at platinum may cause the adsorption of oxygen species, which limits the performance of the collector electrode. To rectify the issues, a pre-treatment step was employed before any analysis was undertaken. This pre-treatment step involved biasing the platinum comb at -0.5 V for ten seconds prior to oxygen measurement. This was done to remove the bound hydrogen peroxide, but also had the benefit of reducing any surface oxide that may have formed during previous scans. A comparison of the collector data for a gold-gold IDE, a gold-platinum IDE that was not pre-treated and a gold-platinum array that was pre-treated is shown in Figure . Each of these scans had been performed in ADW with equivalent concentrations of dissolved oxygen. It is evident that the pre-treatment step is critical to ensure enhanced detection of hydrogen peroxide at the collector electrode. Having established the correct pre-treatment parameters, the effect of varying the collector potential was also investigated. From the initial work with H2O2 it was expected that a bias of 0.7 V would give the highest current, but ultimately it was determined that 0.4 V was more than sufficient, as shown in Figure (a) inset. The Au-Pt arrays were subjected to varying concentrations of DO in ADW. Figure shows the generator CV result for the gold comb of electrodes, showing oxygen reduction at various DO concentrations. As with the initial tests on gold in GC mode, the amplification of the H2O2 generation step is seen as a result of redox cycling, particularly at high DO concentrations. The calibration plot of Figure (a) is included in the supplementary information (SI , and exhibited a sensitivity of 4.11 nA/ppm, which is higher than those discussed previously for gold or platinum in single mode. This indicates that the redox cycling approach is more sensitive to DO, without yet taking advantage of the collector for interference elimination. Figure (b) shows the resultant collector scans recorded on platinum (at 0.4 V) while the generator was undergoing CV. The oxidation event observed at -0.5 V is shown to scale with the DO concentration and occurs when the generator is reducing DO. The oxidation event observed at ~0.3 V seems to be in response to the gold oxide reduction occurring on the generator electrode which was only observed on the first CV sweep and not present in subsequent sweeps, which is shown in Supporting Information (SI Fig7 (a) and (b)). Figure (c) shows that the current associated with this event is linearly proportional to the amount of DO presence in the solution, with a sensitivity of 1.49 nA/ppm. (R 2 = 0.98). A limit of detection for this method of 0.36 ppm was calculated by using the formula (3.3)(σ)/Slope, where the σ was calculated by 7 replicates of the 1 ppm sample.