Non-obvious Problems in Clark Electrode Application at Elevated Temperature and Ways of Their Elimination

Figure 3

Thermostated measuring cell: (1) is oxygen sensor (Figure 2, a cathode is not shown), (2) is measuring cell (PMMA), (3) is magnetic stirrer, (4) is heat carrier from thermostat, (5) is conditional incubation medium (KCl; 60 g/L, 3.5 mL), and (6) is electrolyte of the sensor (KCl; 60 g/L, 400 μL). (a) is circulation of heat carrier, (b) is mixing of the medium by a magnetic stirrer, and (c) is convective mixing of the electrolyte due to a temperature difference between the membrane and the sensor’s body. The temperature gradient between the heated incubation medium (5) and colder electrolyte (6) of oxygen sensor (1) causes convective mixing of the electrolyte (c). This significantly accelerates the gas exchange between the electrolyte and the medium [23].