An improved Clark-type galvanic sensor for dissolved oxygen

Clark-type galvanic oxygen sensor has been fabricated, in which the indicator electrode is made from an industrially produced Ni-Cu alloy containing approximate to 30% Ni. The exposed area of the tubular-shaped indicator electrode is about 10 cm(2). The anode is prepared from cadmium. The sensor is filled with 6 M aqueous KOH solution. The 95% response time of the device is on average 50 s, its residual current at zero oxygen concentration is negligible, its lifetime is one to two years, its output-current variation is less than 5% in a one-year period and an excellent linear calibration curve for oxygen concentrations in the range 0-17 mg l(-1) is observed.