Novel approaches to galvanic oxygen analysis
This communication describes two modifications of a remarkably inexpensive galvanic membrane-covered oxygen sensor, presented in a recent paper. An oxygen sensor and a corresponding simple device were developed for extending the measurement range to less than 1 µg l–1. In this sensor a tubular supporting cathode from Ni—Cu alloy was located under a tubular cathode. The current in the circuit supporting cathode-anode was opposed to the current in the circuit cathode-anode, so automatically eliminating the residual current caused by the reduction of impurities and traces of oxygen in the electrolyte solution. With the aim of developing an oxygen sensor for low temperatures an electrolyte solution, containing C2H5OH, KOH and H2O, was utilized for filling the interior of the sensor, so preventing the freezing of the electrolyte solution at low temperatures (up to –40 °C). The operating characteristics of the trial sensors were equal or even better than those of the basic construction.