To assess interference effects, a sample of river water was collected and tested using the Au-Pt GC method. River water was taken directly from the estuary at River Lee in Cork at low tide, when the water was slow moving, in early May. Low tide was chosen for two main reasons:(i) contaminants present would likely exist in the greatest concentrations. (ii) DO concentration of running water is significantly higher than that of stagnant or slow moving water. Figure shows voltammograms for equivalent tests performed in both ADW and the river water samples. In both samples, DO concentrations were ~ 4.5 ppm, confirmed by using the optical DO probe, with the ADW requiring a moderate purge to match the river water sample. The river water sample was allowed to reach room temperature before any measurement was taken. This likely would have changed the DO concentration, as water dissolves more oxygen at lower temperatures. However, as this test was only being done to compare the effectiveness of the method and not get representative data of actual water quality, this was not a concern for this approach at this time. The generator scans in Figure (a), show a clear and significant increase in current is observed for the river water sample when compared to the ADW. This is attributed to other chemical interferent species being present in the water samples that may contribute to the increased reduction current and thus providing a false positive result. Figure (b) shows the equivalent collector scans measured as the generator electrode was scanned. Very little deviation is observed for the current measured in comparison to the generator current. Using the calibration of the generator current described in supporting Information (SI Fig7 (a)) the difference in current at the generator electrode equates to a 3.4 ppm over estimation in the DO concentration. The collector signal, however, shows a 0.6 ppm underestimation of the DO concentration. Considering the difficulty associated with keeping samples at set DO concentrations, 0.6 ppm could be the result of experimental error whereas 3.4 ppm is not negligible. An issue that was observed for the river water samples was electrode fouling. This can be observed in supporting Information (SI Fig7 (b)) on the reverse sweep for the river water, which shows a much lower reverse peak than the ADW. This was rectifiable by the pre-treatment step, Tests were performed with ADW samples that included known concentrations of reductive interferents. In this case, ADW samples were spiked with 1 ppm each of NaOCl and FeCl3. Figure shows a bar chart of the resulting generator and collector signals. The blank measurement in ADW is considered 100%. For this method, to account for the variability of DO, the signals were normalized based on their DO concentrations after they had been spiked with the interferent. In this process, samples were spiked with either NaOCl or FeCl3 and left to sit for 5 minutes before a DO measurement was taken with the commercial probe. The measured DO concentrations were then used to determine a ratio for the resulting measured signals. In both cases, the generator signal increases significantly upon addition of interferent, however, the collector signal remains relatively unchanged. This further indicates the effectiveness of the GC approach for the quantification of DO in water without the need for gas permeable membranes.