Towards a microelectrode sensor for the determination of oxygen in waters

Simple amperometric sensors based on a Pt microdisc cathode (radius, 25 μm) and a reference electrode, either a saturated calomel electrode or an Al electrode, for the determination of dissolved oxygen in water are considered. Such sensors are highly sensitive and have a linear response over the range of oxygen concentrations studied, i.e., 1.5–8 ppm. It is, however, essential to employ a simple potential pulse sequence to prevent a decay in the output signal with time due to poisoning of the Pt surface.