Application of ruthenium oxide pH sensitive electrode to samples with high redox interference
School of Science
In this work, the E* value of a sputter deposited RuO2 pH sensitive electrode is shown to shift in the presence of oxidising and reducing agents, whilst maintaining a Nernstian response slope from pH 2 to 12. This finding is used to develop a sample-equilibration calibration protocol that allows for the measurement of pH in samples with strong redox agents, such as fresh citrus juice, which could not be measured previously. Additionally, the RuO2 sputter deposition parameters (plasma gas pressure, argon/oxygen gas ratio and material thickness) are investigated for manufacture of a durable solid-state RuO2 pH electrode.